mariadb/mysql-test/main/innodb_mysql_lock2.test

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Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
# This test covers behavior for InnoDB tables.
--source include/have_innodb.inc
# This test requires statement/mixed mode binary logging.
# Row-based mode puts weaker serializability requirements
# so weaker locks are acquired for it.
Fix for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". ALTER TABLE on InnoDB table (including partitioned tables) acquired exclusive locks on rows of table being altered. In cases when there was concurrent transaction which did locking reads from this table this sometimes led to a deadlock which was not detected by MDL subsystem nor by InnoDB engine (and was reported only after exceeding innodb_lock_wait_timeout). This problem stemmed from the fact that ALTER TABLE acquired TL_WRITE_ALLOW_READ lock on table being altered. This lock was interpreted as a write lock and thus for table being altered handler::external_lock() method was called with F_WRLCK as an argument. As result InnoDB engine treated ALTER TABLE as an operation which is going to change data and acquired LOCK_X locks on rows being read from old version of table. In case when there was a transaction which already acquired SR metadata lock on table and some LOCK_S locks on its rows (e.g. by using it in subquery of DML statement) concurrent ALTER TABLE was blocked at the moment when it tried to acquire LOCK_X lock before reading one of these rows. The transaction's attempt to acquire SW metadata lock on table being altered led to deadlock, since it had to wait for ALTER TABLE to release SNW lock. This deadlock was not detected and got resolved only after timeout expiring because waiting were happening in two different subsystems. Similar deadlocks could have occured in other situations. This patch tries to solve the problem by changing ALTER TABLE implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ. After this step handler::external_lock() is called with F_RDLCK as an argument and InnoDB engine correctly interprets ALTER TABLE as operation which only reads data from original version of table. Thanks to this ALTER TABLE acquires only LOCK_S locks on rows it reads. This, in its turn, causes inter-subsystem deadlocks to go away, as all potential lock conflicts and thus deadlocks will be limited to metadata locking subsystem: - When ALTER TABLE reads rows from table being altered it can't encounter any locks which conflict with LOCK_S row locks. There should be no concurrent transactions holding LOCK_X row locks. Such a transaction should have been acquired SW metadata lock on table first which would have conflicted with ALTER's SNW lock. - Vice versa, when DML which runs concurrently with ALTER TABLE tries to lock row it should be requesting only LOCK_S lock which is compatible with locks acquired by ALTER, as otherwise such DML must own an SW metadata lock on table which would be incompatible with ALTER's SNW lock. mysql-test/r/innodb_mysql_lock2.result: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/suite/rpl_ndb/t/rpl_ndb_binlog_format_errors.test: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/t/innodb_mysql_lock2.test: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". sql/ha_partition.cc: When ALTER TABLE creates a new partition to be filled from other partition lock it in F_WRLCK mode instead of using mode which was used for locking the whole table (it is F_RDLCK now). sql/lock.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/mdl.cc: Updated outdated comment to reflect current situation. sql/sql_base.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/sql_table.cc: mysql_admin_table(): Use TL_WRITE_ALLOW_WRITE lock type instead of TL_WRITE_ALLOW_READ to determine that we need to acquire upgradable metadata lock. This should allow to completely get rid of TL_WRITE_ALLOW_READ in long term. mysql_recreate_table(): ALTER TABLE now requires TL_READ_NO_INSERT thr_lock.c lock instead of TL_WRITE_ALLOW_READ. sql/sql_trigger.cc: Changed CREATE/DROP TRIGGER implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. The latter is no longer necessary since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement does not change any data in table so there is no need to inform storage engine about it. sql/sql_yacc.yy: Changed implementation of ALTER TABLE (and CREATE/DROP INDEX as a consequence) to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. This is possible since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement only reads data in table being open. We write data only to the new version of table and then replace with it old version of table under X metadata lock. Thanks to this change InnoDB will no longer acquire LOCK_X locks on rows being read by ALTER TABLE (instead LOCK_S locks will be acquired) and thus cause of bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION" is removed. Did the similar change for CREATE TRIGGER (see comments for sql_trigger.cc for details).
2010-05-26 14:18:08 +02:00
# Also in ROW mode LOCK_S row locks won't be acquired for DML
# and test for bug#51263 won't trigger execution path on which
# this bug was encountered.
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
--source include/have_binlog_format_mixed_or_statement.inc
Fix for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". ALTER TABLE on InnoDB table (including partitioned tables) acquired exclusive locks on rows of table being altered. In cases when there was concurrent transaction which did locking reads from this table this sometimes led to a deadlock which was not detected by MDL subsystem nor by InnoDB engine (and was reported only after exceeding innodb_lock_wait_timeout). This problem stemmed from the fact that ALTER TABLE acquired TL_WRITE_ALLOW_READ lock on table being altered. This lock was interpreted as a write lock and thus for table being altered handler::external_lock() method was called with F_WRLCK as an argument. As result InnoDB engine treated ALTER TABLE as an operation which is going to change data and acquired LOCK_X locks on rows being read from old version of table. In case when there was a transaction which already acquired SR metadata lock on table and some LOCK_S locks on its rows (e.g. by using it in subquery of DML statement) concurrent ALTER TABLE was blocked at the moment when it tried to acquire LOCK_X lock before reading one of these rows. The transaction's attempt to acquire SW metadata lock on table being altered led to deadlock, since it had to wait for ALTER TABLE to release SNW lock. This deadlock was not detected and got resolved only after timeout expiring because waiting were happening in two different subsystems. Similar deadlocks could have occured in other situations. This patch tries to solve the problem by changing ALTER TABLE implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ. After this step handler::external_lock() is called with F_RDLCK as an argument and InnoDB engine correctly interprets ALTER TABLE as operation which only reads data from original version of table. Thanks to this ALTER TABLE acquires only LOCK_S locks on rows it reads. This, in its turn, causes inter-subsystem deadlocks to go away, as all potential lock conflicts and thus deadlocks will be limited to metadata locking subsystem: - When ALTER TABLE reads rows from table being altered it can't encounter any locks which conflict with LOCK_S row locks. There should be no concurrent transactions holding LOCK_X row locks. Such a transaction should have been acquired SW metadata lock on table first which would have conflicted with ALTER's SNW lock. - Vice versa, when DML which runs concurrently with ALTER TABLE tries to lock row it should be requesting only LOCK_S lock which is compatible with locks acquired by ALTER, as otherwise such DML must own an SW metadata lock on table which would be incompatible with ALTER's SNW lock. mysql-test/r/innodb_mysql_lock2.result: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/suite/rpl_ndb/t/rpl_ndb_binlog_format_errors.test: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/t/innodb_mysql_lock2.test: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". sql/ha_partition.cc: When ALTER TABLE creates a new partition to be filled from other partition lock it in F_WRLCK mode instead of using mode which was used for locking the whole table (it is F_RDLCK now). sql/lock.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/mdl.cc: Updated outdated comment to reflect current situation. sql/sql_base.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/sql_table.cc: mysql_admin_table(): Use TL_WRITE_ALLOW_WRITE lock type instead of TL_WRITE_ALLOW_READ to determine that we need to acquire upgradable metadata lock. This should allow to completely get rid of TL_WRITE_ALLOW_READ in long term. mysql_recreate_table(): ALTER TABLE now requires TL_READ_NO_INSERT thr_lock.c lock instead of TL_WRITE_ALLOW_READ. sql/sql_trigger.cc: Changed CREATE/DROP TRIGGER implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. The latter is no longer necessary since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement does not change any data in table so there is no need to inform storage engine about it. sql/sql_yacc.yy: Changed implementation of ALTER TABLE (and CREATE/DROP INDEX as a consequence) to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. This is possible since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement only reads data in table being open. We write data only to the new version of table and then replace with it old version of table under X metadata lock. Thanks to this change InnoDB will no longer acquire LOCK_X locks on rows being read by ALTER TABLE (instead LOCK_S locks will be acquired) and thus cause of bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION" is removed. Did the similar change for CREATE TRIGGER (see comments for sql_trigger.cc for details).
2010-05-26 14:18:08 +02:00
# Original test case for bug#51263 needs partitioning.
--source include/have_partition.inc
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
# Save the initial number of concurrent sessions.
--source include/count_sessions.inc
BUG#53259 Unsafe statement binlogged in statement format w/MyIsam temp tables BUG#54872 MBR: replication failure caused by using tmp table inside transaction Changed criteria to classify a statement as unsafe in order to reduce the number of spurious warnings. So a statement is classified as unsafe when there is on-going transaction at any point of the execution if: 1. The mixed statement is about to update a transactional table and a non-transactional table. 2. The mixed statement is about to update a temporary transactional table and a non-transactional table. 3. The mixed statement is about to update a transactional table and read from a non-transactional table. 4. The mixed statement is about to update a temporary transactional table and read from a non-transactional table. 5. The mixed statement is about to update a non-transactional table and read from a transactional table when the isolation level is lower than repeatable read. After updating a transactional table if: 6. The mixed statement is about to update a non-transactional table and read from a temporary transactional table. 7. The mixed statement is about to update a non-transactional table and read from a temporary transactional table. 8. The mixed statement is about to update a non-transactionala table and read from a temporary non-transactional table. 9. The mixed statement is about to update a temporary non-transactional table and update a non-transactional table. 10. The mixed statement is about to update a temporary non-transactional table and read from a non-transactional table. 11. A statement is about to update a non-transactional table and the option variables.binlog_direct_non_trans_update is OFF. The reason for this is that locks acquired may not protected a concurrent transaction of interfering in the current execution and by consequence in the result. So the patch reduced the number of spurious unsafe warnings. Besides we fixed a regression caused by BUG#51894, which makes temporary tables to go into the trx-cache if there is an on-going transaction. In MIXED mode, the patch for BUG#51894 ignores that the trx-cache may have updates to temporary non-transactional tables that must be written to the binary log while rolling back the transaction. So we fix this problem by writing the content of the trx-cache to the binary log while rolling back a transaction if a non-transactional temporary table was updated and the binary logging format is MIXED.
2010-06-30 17:25:13 +02:00
--disable_query_log
CALL mtr.add_suppression("Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT");
--enable_query_log
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
--echo #
--echo # Test how do we handle locking in various cases when
--echo # we read data from InnoDB tables.
--echo #
--echo # In fact by performing this test we check two things:
--echo # 1) That SQL-layer correctly determine type of thr_lock.c
--echo # lock to be acquired/passed to InnoDB engine.
--echo # 2) That InnoDB engine correctly interprets this lock
--echo # type and takes necessary row locks or does not
--echo # take them if they are not necessary.
--echo #
--echo # This test makes sense only in REPEATABLE-READ mode as
--echo # in SERIALIZABLE mode all statements that read data take
--echo # shared lock on them to enforce its semantics.
select @@session.tx_isolation;
--echo # Prepare playground by creating tables, views,
--echo # routines and triggers used in tests.
connect (con1, localhost, root,,);
connection default;
--disable_warnings
drop table if exists t0, t1, t2, t3, t4, t5;
drop view if exists v1, v2;
drop procedure if exists p1;
drop procedure if exists p2;
drop function if exists f1;
drop function if exists f2;
drop function if exists f3;
drop function if exists f4;
drop function if exists f5;
drop function if exists f6;
drop function if exists f7;
drop function if exists f8;
drop function if exists f9;
drop function if exists f10;
drop function if exists f11;
drop function if exists f12;
drop function if exists f13;
drop function if exists f14;
drop function if exists f15;
--enable_warnings
create table t1 (i int primary key) engine=innodb;
insert into t1 values (1), (2), (3), (4), (5);
create table t2 (j int primary key) engine=innodb;
insert into t2 values (1), (2), (3), (4), (5);
create table t3 (k int primary key) engine=innodb;
insert into t3 values (1), (2), (3);
create table t4 (l int primary key) engine=innodb;
insert into t4 values (1);
create table t5 (l int primary key) engine=innodb;
insert into t5 values (1);
create view v1 as select i from t1;
create view v2 as select j from t2 where j in (select i from t1);
create procedure p1(k int) insert into t2 values (k);
delimiter |;
create function f1() returns int
begin
declare j int;
select i from t1 where i = 1 into j;
return j;
end|
create function f2() returns int
begin
declare k int;
select i from t1 where i = 1 into k;
insert into t2 values (k + 5);
return 0;
end|
create function f3() returns int
begin
return (select i from t1 where i = 3);
end|
create function f4() returns int
begin
if (select i from t1 where i = 3) then
return 1;
else
return 0;
end if;
end|
create function f5() returns int
begin
insert into t2 values ((select i from t1 where i = 1) + 5);
return 0;
end|
create function f6() returns int
begin
declare k int;
select i from v1 where i = 1 into k;
return k;
end|
create function f7() returns int
begin
declare k int;
select j from v2 where j = 1 into k;
return k;
end|
create function f8() returns int
begin
declare k int;
select i from v1 where i = 1 into k;
insert into t2 values (k+5);
return k;
end|
create function f9() returns int
begin
update v2 set j=j+10 where j=1;
return 1;
end|
create function f10() returns int
begin
return f1();
end|
create function f11() returns int
begin
declare k int;
set k= f1();
insert into t2 values (k+5);
return k;
end|
create function f12(p int) returns int
begin
insert into t2 values (p);
return p;
end|
create function f13(p int) returns int
begin
return p;
end|
create procedure p2(inout p int)
begin
select i from t1 where i = 1 into p;
end|
create function f14() returns int
begin
declare k int;
call p2(k);
insert into t2 values (k+5);
return k;
end|
create function f15() returns int
begin
declare k int;
call p2(k);
return k;
end|
create trigger t4_bi before insert on t4 for each row
begin
declare k int;
select i from t1 where i=1 into k;
set new.l= k+1;
end|
create trigger t4_bu before update on t4 for each row
begin
if (select i from t1 where i=1) then
set new.l= 2;
end if;
end|
create trigger t4_bd before delete on t4 for each row
begin
if !(select i from v1 where i=1) then
signal sqlstate '45000';
end if;
end|
create trigger t5_bi before insert on t5 for each row
begin
set new.l= f1()+1;
end|
create trigger t5_bu before update on t5 for each row
begin
declare j int;
call p2(j);
set new.l= j + 1;
end|
delimiter ;|
--echo #
--echo # Set common variables to be used by scripts called below.
--echo #
let $con_aux= con1;
let $table= t1;
--echo #
--echo # 1. Statements that read tables and do not use subqueries.
--echo #
--echo #
--echo # 1.1 Simple SELECT statement.
--echo #
--echo # No locks are necessary as this statement won't be written
--echo # to the binary log and InnoDB supports snapshots.
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= select * from t1;
--source include/check_no_row_lock.inc
--echo #
--echo # 1.2 Multi-UPDATE statement.
--echo #
--echo # Has to take shared locks on rows in the table being read as this
--echo # statement will be written to the binary log and therefore should
--echo # be serialized with concurrent statements.
let $statement= update t2, t1 set j= j - 1 where i = j;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 1.3 Multi-DELETE statement.
--echo #
--echo # The above is true for this statement as well.
let $statement= delete t2 from t1, t2 where i = j;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 1.4 DESCRIBE statement.
--echo #
--echo # This statement does not really read data from the
--echo # target table and thus does not take any lock on it.
--echo # We check this for completeness of coverage.
let $statement= describe t1;
--source include/check_no_row_lock.inc
--echo #
--echo # 1.5 SHOW statements.
--echo #
--echo # The above is true for SHOW statements as well.
let $statement= show create table t1;
--source include/check_no_row_lock.inc
let $statement= show keys from t1;
--source include/check_no_row_lock.inc
--echo #
--echo # 2. Statements which read tables through subqueries.
--echo #
--echo #
--echo # 2.1 CALL with a subquery.
--echo #
--echo # A strong lock is not necessary as this statement is not
--echo # written to the binary log as a whole (it is written
--echo # statement-by-statement) and thanks to MVCC we can always get
--echo # versions of rows prior to the update that has locked them.
--echo # But in practice InnoDB does locking reads for all statements
--echo # other than SELECT (unless it is a READ-COMITTED mode or
--echo # innodb_locks_unsafe_for_binlog is ON).
let $statement= call p1((select i + 5 from t1 where i = 1));
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.2 CREATE TABLE with a subquery.
--echo #
--echo # Has to take shared locks on rows in the table being read as
--echo # this statement is written to the binary log and therefore
--echo # should be serialized with concurrent statements.
let $statement= create table t0 engine=innodb select * from t1;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
drop table t0;
let $statement= create table t0 engine=innodb select j from t2 where j in (select i from t1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
drop table t0;
--echo #
--echo # 2.3 DELETE with a subquery.
--echo #
--echo # The above is true for this statement as well.
let $statement= delete from t2 where j in (select i from t1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.4 MULTI-DELETE with a subquery.
--echo #
--echo # Same is true for this statement as well.
let $statement= delete t2 from t3, t2 where k = j and j in (select i from t1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.5 DO with a subquery.
--echo #
--echo # In theory should not take row locks as it is not logged.
--echo # In practice InnoDB takes shared row locks.
let $statement= do (select i from t1 where i = 1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.6 INSERT with a subquery.
--echo #
--echo # Has to take shared locks on rows in the table being read as
--echo # this statement is written to the binary log and therefore
--echo # should be serialized with concurrent statements.
let $statement= insert into t2 select i+5 from t1;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
let $statement= insert into t2 values ((select i+5 from t1 where i = 4));
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.7 LOAD DATA with a subquery.
--echo #
--echo # The above is true for this statement as well.
let $statement= load data infile '../../std_data/rpl_loaddata.dat' into table t2 (@a, @b) set j= @b + (select i from t1 where i = 1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.8 REPLACE with a subquery.
--echo #
--echo # Same is true for this statement as well.
let $statement= replace into t2 select i+5 from t1;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
let $statement= replace into t2 values ((select i+5 from t1 where i = 4));
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.9 SELECT with a subquery.
--echo #
--echo # Locks are not necessary as this statement is not written
--echo # to the binary log and thanks to MVCC we can always get
--echo # versions of rows prior to the update that has locked them.
--echo #
--echo # Also serves as a test case for bug #46947 "Embedded SELECT
--echo # without FOR UPDATE is causing a lock".
let $statement= select * from t2 where j in (select i from t1);
--source include/check_no_row_lock.inc
--echo #
--echo # 2.10 SET with a subquery.
--echo #
--echo # In theory should not require locking as it is not written
--echo # to the binary log. In practice InnoDB acquires shared row
--echo # locks.
let $statement= set @a:= (select i from t1 where i = 1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.11 SHOW with a subquery.
--echo #
--echo # Similarly to the previous case, in theory should not require locking
--echo # as it is not written to the binary log. In practice InnoDB
--echo # acquires shared row locks.
let $statement= show tables from test where Tables_in_test = 't2' and (select i from t1 where i = 1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
let $statement= show columns from t2 where (select i from t1 where i = 1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.12 UPDATE with a subquery.
--echo #
--echo # Has to take shared locks on rows in the table being read as
--echo # this statement is written to the binary log and therefore
--echo # should be serialized with concurrent statements.
let $statement= update t2 set j= j-10 where j in (select i from t1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 2.13 MULTI-UPDATE with a subquery.
--echo #
--echo # Same is true for this statement as well.
let $statement= update t2, t3 set j= j -10 where j=k and j in (select i from t1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 3. Statements which read tables through a view.
--echo #
--echo #
--echo # 3.1 SELECT statement which uses some table through a view.
--echo #
--echo # Since this statement is not written to the binary log
--echo # and old version of rows are accessible thanks to MVCC,
--echo # no locking is necessary.
let $statement= select * from v1;
--source include/check_no_row_lock.inc
let $statement= select * from v2;
--source include/check_no_row_lock.inc
let $statement= select * from t2 where j in (select i from v1);
--source include/check_no_row_lock.inc
let $statement= select * from t3 where k in (select j from v2);
--source include/check_no_row_lock.inc
--echo #
--echo # 3.2 Statements which modify a table and use views.
--echo #
--echo # Since such statements are going to be written to the binary
--echo # log they need to be serialized against concurrent statements
--echo # and therefore should take shared row locks on data read.
let $statement= update t2 set j= j-10 where j in (select i from v1);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
let $statement= update t3 set k= k-10 where k in (select j from v2);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
let $statement= update t2, v1 set j= j-10 where j = i;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
let $statement= update v2 set j= j-10 where j = 3;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4. Statements which read tables through stored functions.
--echo #
--echo #
--echo # 4.1 SELECT/SET with a stored function which does not
--echo # modify data and uses SELECT in its turn.
--echo #
--echo # There is no need to take row locks on the table
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
--echo # being selected from in SF as the call to such function
--echo # won't get into the binary log.
--echo #
--echo # However in practice innodb takes strong lock on tables
--echo # being selected from within SF, when SF is called from
--echo # non SELECT statements like 'set' statement below.
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= select f1();
let $wait_statement= select i from t1 where i = 1 into j;
--source include/check_no_row_lock.inc
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= set @a:= f1();
let $wait_statement= select i from t1 where i = 1 into j;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.2 INSERT (or other statement which modifies data) with
--echo # a stored function which does not modify data and uses
--echo # SELECT.
--echo #
--echo # Since such statement is written to the binary log it should
--echo # be serialized with concurrent statements affecting the data
--echo # it uses. Therefore it should take row locks on the data
--echo # it reads.
let $statement= insert into t2 values (f1() + 5);
let $wait_statement= select i from t1 where i = 1 into j;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.3 SELECT/SET with a stored function which
--echo # reads and modifies data.
--echo #
--echo # Since a call to such function is written to the binary log,
--echo # it should be serialized with concurrent statements affecting
--echo # the data it uses. Hence, row locks on the data read
--echo # should be taken.
let $statement= select f2();
let $wait_statement= select i from t1 where i = 1 into k;
--source include/check_shared_row_lock.inc
let $statement= set @a:= f2();
let $wait_statement= select i from t1 where i = 1 into k;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.4. SELECT/SET with a stored function which does not
--echo # modify data and reads a table through subselect
--echo # in a control construct.
--echo #
--echo # Call to this function won't get to the
--echo # binary log and thus no locking is needed.
--echo #
--echo # However in practice innodb takes strong lock on tables
--echo # being selected from within SF, when SF is called from
--echo # non SELECT statements like 'set' statement below.
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= select f3();
let $wait_statement= $statement;
--source include/check_no_row_lock.inc
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= set @a:= f3();
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
let $statement= select f4();
let $wait_statement= $statement;
--source include/check_no_row_lock.inc
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= set @a:= f4();
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.5. INSERT (or other statement which modifies data) with
--echo # a stored function which does not modify data and reads
--echo # the table through a subselect in one of its control
--echo # constructs.
--echo #
--echo # Since such statement is written to the binary log it should
--echo # be serialized with concurrent statements affecting data it
--echo # uses. Therefore it should take row locks on the data
--echo # it reads.
let $statement= insert into t2 values (f3() + 5);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
let $statement= insert into t2 values (f4() + 6);
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.6 SELECT/SET which uses a stored function with
--echo # DML which reads a table via a subquery.
--echo #
--echo # Since call to such function is written to the binary log
--echo # it should be serialized with concurrent statements.
--echo # Hence reads should take row locks.
let $statement= select f5();
let $wait_statement= insert into t2 values ((select i from t1 where i = 1) + 5);
--source include/check_shared_row_lock.inc
let $statement= set @a:= f5();
let $wait_statement= insert into t2 values ((select i from t1 where i = 1) + 5);
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.7 SELECT/SET which uses a stored function which
--echo # doesn't modify data and reads tables through
--echo # a view.
--echo #
--echo # Calls to such functions won't get into
--echo # the binary log and thus don't need row locks.
--echo #
--echo # However in practice innodb takes strong lock on tables
--echo # being selected from within SF, when SF is called from
--echo # non SELECT statements like 'set' statement below.
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= select f6();
let $wait_statement= select i from v1 where i = 1 into k;
--source include/check_no_row_lock.inc
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= set @a:= f6();
let $wait_statement= select i from v1 where i = 1 into k;
--source include/check_shared_row_lock.inc
let $statement= select f7();
let $wait_statement= select j from v2 where j = 1 into k;
--source include/check_no_row_lock.inc
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= set @a:= f7();
let $wait_statement= select j from v2 where j = 1 into k;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.8 INSERT which uses stored function which
--echo # doesn't modify data and reads a table
--echo # through a view.
--echo #
--echo # Since such statement is written to the binary log and
--echo # should be serialized with concurrent statements affecting
--echo # the data it uses. Therefore it should take row locks on
--echo # the rows it reads.
let $statement= insert into t3 values (f6() + 5);
let $wait_statement= select i from v1 where i = 1 into k;
--source include/check_shared_row_lock.inc
let $statement= insert into t3 values (f7() + 5);
let $wait_statement= select j from v2 where j = 1 into k;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.9 SELECT which uses a stored function which
--echo # modifies data and reads tables through a view.
--echo #
--echo # Since a call to such function is written to the binary log
--echo # it should be serialized with concurrent statements.
--echo # Hence, reads should take row locks.
let $statement= select f8();
let $wait_statement= select i from v1 where i = 1 into k;
--source include/check_shared_row_lock.inc
let $statement= select f9();
let $wait_statement= update v2 set j=j+10 where j=1;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.10 SELECT which uses stored function which doesn't modify
--echo # data and reads a table indirectly, by calling another
--echo # function.
--echo #
--echo # Calls to such functions won't get into the binary
--echo # log and thus don't need to acquire row locks.
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= select f10();
let $wait_statement= select i from t1 where i = 1 into j;
--source include/check_no_row_lock.inc
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
--echo #
--echo # 4.11 INSERT which uses a stored function which doesn't modify
--echo # data and reads a table indirectly, by calling another
--echo # function.
--echo #
--echo # Since such statement is written to the binary log, it should
--echo # be serialized with concurrent statements affecting the data it
--echo # uses. Therefore it should take row locks on data it reads.
let $statement= insert into t2 values (f10() + 5);
let $wait_statement= select i from t1 where i = 1 into j;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.12 SELECT which uses a stored function which modifies
--echo # data and reads a table indirectly, by calling another
--echo # function.
--echo #
--echo # Since a call to such function is written to the binary log
--echo # it should be serialized from concurrent statements.
--echo # Hence, reads should take row locks.
let $statement= select f11();
let $wait_statement= select i from t1 where i = 1 into j;
--source include/check_shared_row_lock.inc
--echo #
--echo # 4.13 SELECT that reads a table through a subquery passed
--echo # as a parameter to a stored function which modifies
--echo # data.
--echo #
--echo # Even though a call to this function is written to the
--echo # binary log, values of its parameters are written as literals.
--echo # So there is no need to acquire row locks on rows used in
--echo # the subquery.
let $statement= select f12((select i+10 from t1 where i=1));
--source include/check_no_row_lock.inc
--echo #
--echo # 4.14 INSERT that reads a table via a subquery passed
--echo # as a parameter to a stored function which doesn't
--echo # modify data.
--echo #
--echo # Since this statement is written to the binary log it should
--echo # be serialized with concurrent statements affecting the data it
--echo # uses. Therefore it should take row locks on the data it reads.
let $statement= insert into t2 values (f13((select i+10 from t1 where i=1)));
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 5. Statements that read tables through stored procedures.
--echo #
--echo #
--echo # 5.1 CALL statement which reads a table via SELECT.
--echo #
--echo # Since neither this statement nor its components are
--echo # written to the binary log, there is no need to take
--echo # row locks on the data it reads.
let $statement= call p2(@a);
--source include/check_no_row_lock.inc
--echo #
--echo # 5.2 Function that modifies data and uses CALL,
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
--echo # which reads a table through SELECT.
--echo #
--echo # Since a call to such function is written to the binary
--echo # log, it should be serialized with concurrent statements.
--echo # Hence, in this case reads should take row locks on data.
let $statement= select f14();
let $wait_statement= select i from t1 where i = 1 into p;
--source include/check_shared_row_lock.inc
--echo #
--echo # 5.3 SELECT that calls a function that doesn't modify data and
--echo # uses a CALL statement that reads a table via SELECT.
--echo #
--echo # Calls to such functions won't get into the binary
--echo # log and thus don't need to acquire row locks.
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
let $statement= select f15();
let $wait_statement= select i from t1 where i = 1 into p;
--source include/check_no_row_lock.inc
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
--echo #
--echo # 5.4 INSERT which calls function which doesn't modify data and
--echo # uses CALL statement which reads table through SELECT.
--echo #
--echo # Since such statement is written to the binary log it should
--echo # be serialized with concurrent statements affecting data it
--echo # uses. Therefore it should take row locks on data it reads.
let $statement= insert into t2 values (f15()+5);
let $wait_statement= select i from t1 where i = 1 into p;
--source include/check_shared_row_lock.inc
--echo #
--echo # 6. Statements that use triggers.
--echo #
--echo #
--echo # 6.1 Statement invoking a trigger that reads table via SELECT.
--echo #
--echo # Since this statement is written to the binary log it should
--echo # be serialized with concurrent statements affecting the data
--echo # it uses. Therefore, it should take row locks on the data
--echo # it reads.
let $statement= insert into t4 values (2);
let $wait_statement= select i from t1 where i=1 into k;
--source include/check_shared_row_lock.inc
--echo #
--echo # 6.2 Statement invoking a trigger that reads table through
--echo # a subquery in a control construct.
--echo #
--echo # The above is true for this statement as well.
let $statement= update t4 set l= 2 where l = 1;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 6.3 Statement invoking a trigger that reads a table through
--echo # a view.
--echo #
--echo # And for this statement.
let $statement= delete from t4 where l = 1;
let $wait_statement= $statement;
--source include/check_shared_row_lock.inc
--echo #
--echo # 6.4 Statement invoking a trigger that reads a table through
--echo # a stored function.
--echo #
--echo # And for this statement.
let $statement= insert into t5 values (2);
let $wait_statement= select i from t1 where i = 1 into j;
--source include/check_shared_row_lock.inc
--echo #
--echo # 6.5 Statement invoking a trigger that reads a table through
--echo # stored procedure.
--echo #
--echo # And for this statement.
let $statement= update t5 set l= 2 where l = 1;
let $wait_statement= select i from t1 where i = 1 into p;
--source include/check_shared_row_lock.inc
--echo # Clean-up.
drop function f1;
drop function f2;
drop function f3;
drop function f4;
drop function f5;
drop function f6;
drop function f7;
drop function f8;
drop function f9;
drop function f10;
drop function f11;
drop function f12;
drop function f13;
drop function f14;
drop function f15;
drop view v1, v2;
drop procedure p1;
drop procedure p2;
drop table t1, t2, t3, t4, t5;
disconnect con1;
Fix for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". ALTER TABLE on InnoDB table (including partitioned tables) acquired exclusive locks on rows of table being altered. In cases when there was concurrent transaction which did locking reads from this table this sometimes led to a deadlock which was not detected by MDL subsystem nor by InnoDB engine (and was reported only after exceeding innodb_lock_wait_timeout). This problem stemmed from the fact that ALTER TABLE acquired TL_WRITE_ALLOW_READ lock on table being altered. This lock was interpreted as a write lock and thus for table being altered handler::external_lock() method was called with F_WRLCK as an argument. As result InnoDB engine treated ALTER TABLE as an operation which is going to change data and acquired LOCK_X locks on rows being read from old version of table. In case when there was a transaction which already acquired SR metadata lock on table and some LOCK_S locks on its rows (e.g. by using it in subquery of DML statement) concurrent ALTER TABLE was blocked at the moment when it tried to acquire LOCK_X lock before reading one of these rows. The transaction's attempt to acquire SW metadata lock on table being altered led to deadlock, since it had to wait for ALTER TABLE to release SNW lock. This deadlock was not detected and got resolved only after timeout expiring because waiting were happening in two different subsystems. Similar deadlocks could have occured in other situations. This patch tries to solve the problem by changing ALTER TABLE implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ. After this step handler::external_lock() is called with F_RDLCK as an argument and InnoDB engine correctly interprets ALTER TABLE as operation which only reads data from original version of table. Thanks to this ALTER TABLE acquires only LOCK_S locks on rows it reads. This, in its turn, causes inter-subsystem deadlocks to go away, as all potential lock conflicts and thus deadlocks will be limited to metadata locking subsystem: - When ALTER TABLE reads rows from table being altered it can't encounter any locks which conflict with LOCK_S row locks. There should be no concurrent transactions holding LOCK_X row locks. Such a transaction should have been acquired SW metadata lock on table first which would have conflicted with ALTER's SNW lock. - Vice versa, when DML which runs concurrently with ALTER TABLE tries to lock row it should be requesting only LOCK_S lock which is compatible with locks acquired by ALTER, as otherwise such DML must own an SW metadata lock on table which would be incompatible with ALTER's SNW lock. mysql-test/r/innodb_mysql_lock2.result: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/suite/rpl_ndb/t/rpl_ndb_binlog_format_errors.test: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/t/innodb_mysql_lock2.test: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". sql/ha_partition.cc: When ALTER TABLE creates a new partition to be filled from other partition lock it in F_WRLCK mode instead of using mode which was used for locking the whole table (it is F_RDLCK now). sql/lock.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/mdl.cc: Updated outdated comment to reflect current situation. sql/sql_base.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/sql_table.cc: mysql_admin_table(): Use TL_WRITE_ALLOW_WRITE lock type instead of TL_WRITE_ALLOW_READ to determine that we need to acquire upgradable metadata lock. This should allow to completely get rid of TL_WRITE_ALLOW_READ in long term. mysql_recreate_table(): ALTER TABLE now requires TL_READ_NO_INSERT thr_lock.c lock instead of TL_WRITE_ALLOW_READ. sql/sql_trigger.cc: Changed CREATE/DROP TRIGGER implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. The latter is no longer necessary since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement does not change any data in table so there is no need to inform storage engine about it. sql/sql_yacc.yy: Changed implementation of ALTER TABLE (and CREATE/DROP INDEX as a consequence) to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. This is possible since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement only reads data in table being open. We write data only to the new version of table and then replace with it old version of table under X metadata lock. Thanks to this change InnoDB will no longer acquire LOCK_X locks on rows being read by ALTER TABLE (instead LOCK_S locks will be acquired) and thus cause of bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION" is removed. Did the similar change for CREATE TRIGGER (see comments for sql_trigger.cc for details).
2010-05-26 14:18:08 +02:00
--echo #
--echo # Test for bug#51263 "Deadlock between transactional SELECT
--echo # and ALTER TABLE ... REBUILD PARTITION".
--echo #
connect (con1,localhost,root,,test,,);
connection default;
--disable_warnings
drop table if exists t1, t2;
--enable_warnings
create table t1 (i int auto_increment not null primary key) engine=innodb;
create table t2 (i int) engine=innodb;
insert into t1 values (1), (2), (3), (4), (5);
begin;
--echo # Acquire SR metadata lock on t1 and LOCK_S row-locks on its rows.
insert into t2 select count(*) from t1;
connection con1;
--echo # Sending:
--send alter table t1 add column j int
connection default;
--echo # Wait until ALTER is blocked because it tries to upgrade SNW
--echo # metadata lock to X lock.
--echo # It should not be blocked during copying data to new version of
--echo # table as it acquires LOCK_S locks on rows of old version, which
--echo # are compatible with locks acquired by connection 'con1'.
let $wait_condition=
Part of fix for bug#52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible" to be pushed as separate patch. Replaced thread state name "Waiting for table", which was used by threads waiting for a metadata lock or table flush, with a set of names which better reflect types of resources being waited for. Also replaced "Table lock" thread state name, which was used by threads waiting on thr_lock.c table level lock, with more elaborate "Waiting for table level lock", to make it more consistent with other thread state names. Updated test cases and their results according to these changes. Fixed sys_vars.query_cache_wlock_invalidate_func test to not to wait for timeout of wait_condition.inc script. mysql-test/r/query_cache.result: Added test coverage for query_cache_wlock_invalidate behavior for implicitly locked tables. mysql-test/suite/sys_vars/r/query_cache_wlock_invalidate_func.result: Fixed sys_vars.query_cache_wlock_invalidate_func test to not to wait for timeout of wait_condition.inc script. Reverted changes to test which introduced timeout and replaced waiting condition with a more appropriate one. Test coverage for query_cache_wlock_invalidate behavior for implicitly locked tables was added to query_cache.test. mysql-test/suite/sys_vars/t/query_cache_wlock_invalidate_func.test: Fixed sys_vars.query_cache_wlock_invalidate_func test to not to wait for timeout of wait_condition.inc script. Reverted changes to test which introduced timeout and replaced waiting condition with a more appropriate one. Test coverage for query_cache_wlock_invalidate behavior for implicitly locked tables was added to query_cache.test. mysql-test/t/query_cache.test: Added test coverage for query_cache_wlock_invalidate behavior for implicitly locked tables. mysys/thr_lock.c: Replaced "Table lock" thread state name, which was used by threads waiting on thr_lock.c table level lock, with more elaborate "Waiting for table level lock", to make it consistent with thread state names which are used while waiting for metadata locks and table flush. sql/mdl.cc: Replaced thread state name "Waiting for table", which was used by threads waiting for a metadata lock or table flush, with a set of names which better reflect types of resources being waited for. To implement this: - Adjusted MDL_wait::timed_wait() to take thread state name as parameter. - Introduced method of MDL_key class which allows to get thread state name to be used while waiting for resource corresponding to the key and changed code to use it. Added array translating namespaces to thread state names as part of this change. sql/mdl.h: To implement this: - Adjusted MDL_wait::timed_wait() to take thread state name as parameter. - Introduced method of MDL_key class which allows to get thread state name to be used while waiting for resource corresponding to the key and changed code to use it. Added array translating namespaces to thread state names as part of this change. sql/sql_base.cc: Replaced thread state name "Waiting for table", which was used by threads waiting for table flush, with a more elaborate "Waiting for table flush".
2010-08-06 13:29:37 +02:00
select count(*) = 1 from information_schema.processlist
where state = "Waiting for table metadata lock" and
info = "alter table t1 add column j int";
Fix for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". ALTER TABLE on InnoDB table (including partitioned tables) acquired exclusive locks on rows of table being altered. In cases when there was concurrent transaction which did locking reads from this table this sometimes led to a deadlock which was not detected by MDL subsystem nor by InnoDB engine (and was reported only after exceeding innodb_lock_wait_timeout). This problem stemmed from the fact that ALTER TABLE acquired TL_WRITE_ALLOW_READ lock on table being altered. This lock was interpreted as a write lock and thus for table being altered handler::external_lock() method was called with F_WRLCK as an argument. As result InnoDB engine treated ALTER TABLE as an operation which is going to change data and acquired LOCK_X locks on rows being read from old version of table. In case when there was a transaction which already acquired SR metadata lock on table and some LOCK_S locks on its rows (e.g. by using it in subquery of DML statement) concurrent ALTER TABLE was blocked at the moment when it tried to acquire LOCK_X lock before reading one of these rows. The transaction's attempt to acquire SW metadata lock on table being altered led to deadlock, since it had to wait for ALTER TABLE to release SNW lock. This deadlock was not detected and got resolved only after timeout expiring because waiting were happening in two different subsystems. Similar deadlocks could have occured in other situations. This patch tries to solve the problem by changing ALTER TABLE implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ. After this step handler::external_lock() is called with F_RDLCK as an argument and InnoDB engine correctly interprets ALTER TABLE as operation which only reads data from original version of table. Thanks to this ALTER TABLE acquires only LOCK_S locks on rows it reads. This, in its turn, causes inter-subsystem deadlocks to go away, as all potential lock conflicts and thus deadlocks will be limited to metadata locking subsystem: - When ALTER TABLE reads rows from table being altered it can't encounter any locks which conflict with LOCK_S row locks. There should be no concurrent transactions holding LOCK_X row locks. Such a transaction should have been acquired SW metadata lock on table first which would have conflicted with ALTER's SNW lock. - Vice versa, when DML which runs concurrently with ALTER TABLE tries to lock row it should be requesting only LOCK_S lock which is compatible with locks acquired by ALTER, as otherwise such DML must own an SW metadata lock on table which would be incompatible with ALTER's SNW lock. mysql-test/r/innodb_mysql_lock2.result: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/suite/rpl_ndb/t/rpl_ndb_binlog_format_errors.test: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/t/innodb_mysql_lock2.test: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". sql/ha_partition.cc: When ALTER TABLE creates a new partition to be filled from other partition lock it in F_WRLCK mode instead of using mode which was used for locking the whole table (it is F_RDLCK now). sql/lock.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/mdl.cc: Updated outdated comment to reflect current situation. sql/sql_base.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/sql_table.cc: mysql_admin_table(): Use TL_WRITE_ALLOW_WRITE lock type instead of TL_WRITE_ALLOW_READ to determine that we need to acquire upgradable metadata lock. This should allow to completely get rid of TL_WRITE_ALLOW_READ in long term. mysql_recreate_table(): ALTER TABLE now requires TL_READ_NO_INSERT thr_lock.c lock instead of TL_WRITE_ALLOW_READ. sql/sql_trigger.cc: Changed CREATE/DROP TRIGGER implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. The latter is no longer necessary since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement does not change any data in table so there is no need to inform storage engine about it. sql/sql_yacc.yy: Changed implementation of ALTER TABLE (and CREATE/DROP INDEX as a consequence) to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. This is possible since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement only reads data in table being open. We write data only to the new version of table and then replace with it old version of table under X metadata lock. Thanks to this change InnoDB will no longer acquire LOCK_X locks on rows being read by ALTER TABLE (instead LOCK_S locks will be acquired) and thus cause of bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION" is removed. Did the similar change for CREATE TRIGGER (see comments for sql_trigger.cc for details).
2010-05-26 14:18:08 +02:00
--source include/wait_condition.inc
--echo # The below statement will deadlock because it will try to acquire
--echo # SW lock on t1, which will conflict with ALTER's SNW lock. And
--echo # ALTER will be waiting for this connection to release its SR lock.
--echo # This deadlock should be detected by an MDL subsystem and this
--echo # statement should be aborted with an appropriate error.
--error ER_LOCK_DEADLOCK
insert into t1 values (6);
--echo # Unblock ALTER TABLE.
commit;
connection con1;
--echo # Reaping ALTER TABLE.
--reap
connection default;
--echo #
--echo # Now test for scenario in which bug was reported originally.
--echo #
drop tables t1, t2;
create table t1 (i int auto_increment not null primary key) engine=innodb
partition by hash (i) partitions 4;
create table t2 (i int) engine=innodb;
insert into t1 values (1), (2), (3), (4), (5);
begin;
--echo # Acquire SR metadata lock on t1.
select * from t1;
connection con1;
--echo # Sending:
--send alter table t1 rebuild partition p0
connection default;
--echo # Wait until ALTER is blocked because of active SR lock.
let $wait_condition=
select count(*) = 1 from information_schema.processlist
Part of fix for bug#52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible" to be pushed as separate patch. Replaced thread state name "Waiting for table", which was used by threads waiting for a metadata lock or table flush, with a set of names which better reflect types of resources being waited for. Also replaced "Table lock" thread state name, which was used by threads waiting on thr_lock.c table level lock, with more elaborate "Waiting for table level lock", to make it more consistent with other thread state names. Updated test cases and their results according to these changes. Fixed sys_vars.query_cache_wlock_invalidate_func test to not to wait for timeout of wait_condition.inc script. mysql-test/r/query_cache.result: Added test coverage for query_cache_wlock_invalidate behavior for implicitly locked tables. mysql-test/suite/sys_vars/r/query_cache_wlock_invalidate_func.result: Fixed sys_vars.query_cache_wlock_invalidate_func test to not to wait for timeout of wait_condition.inc script. Reverted changes to test which introduced timeout and replaced waiting condition with a more appropriate one. Test coverage for query_cache_wlock_invalidate behavior for implicitly locked tables was added to query_cache.test. mysql-test/suite/sys_vars/t/query_cache_wlock_invalidate_func.test: Fixed sys_vars.query_cache_wlock_invalidate_func test to not to wait for timeout of wait_condition.inc script. Reverted changes to test which introduced timeout and replaced waiting condition with a more appropriate one. Test coverage for query_cache_wlock_invalidate behavior for implicitly locked tables was added to query_cache.test. mysql-test/t/query_cache.test: Added test coverage for query_cache_wlock_invalidate behavior for implicitly locked tables. mysys/thr_lock.c: Replaced "Table lock" thread state name, which was used by threads waiting on thr_lock.c table level lock, with more elaborate "Waiting for table level lock", to make it consistent with thread state names which are used while waiting for metadata locks and table flush. sql/mdl.cc: Replaced thread state name "Waiting for table", which was used by threads waiting for a metadata lock or table flush, with a set of names which better reflect types of resources being waited for. To implement this: - Adjusted MDL_wait::timed_wait() to take thread state name as parameter. - Introduced method of MDL_key class which allows to get thread state name to be used while waiting for resource corresponding to the key and changed code to use it. Added array translating namespaces to thread state names as part of this change. sql/mdl.h: To implement this: - Adjusted MDL_wait::timed_wait() to take thread state name as parameter. - Introduced method of MDL_key class which allows to get thread state name to be used while waiting for resource corresponding to the key and changed code to use it. Added array translating namespaces to thread state names as part of this change. sql/sql_base.cc: Replaced thread state name "Waiting for table", which was used by threads waiting for table flush, with a more elaborate "Waiting for table flush".
2010-08-06 13:29:37 +02:00
where state = "Waiting for table metadata lock" and
info = "alter table t1 rebuild partition p0";
Fix for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". ALTER TABLE on InnoDB table (including partitioned tables) acquired exclusive locks on rows of table being altered. In cases when there was concurrent transaction which did locking reads from this table this sometimes led to a deadlock which was not detected by MDL subsystem nor by InnoDB engine (and was reported only after exceeding innodb_lock_wait_timeout). This problem stemmed from the fact that ALTER TABLE acquired TL_WRITE_ALLOW_READ lock on table being altered. This lock was interpreted as a write lock and thus for table being altered handler::external_lock() method was called with F_WRLCK as an argument. As result InnoDB engine treated ALTER TABLE as an operation which is going to change data and acquired LOCK_X locks on rows being read from old version of table. In case when there was a transaction which already acquired SR metadata lock on table and some LOCK_S locks on its rows (e.g. by using it in subquery of DML statement) concurrent ALTER TABLE was blocked at the moment when it tried to acquire LOCK_X lock before reading one of these rows. The transaction's attempt to acquire SW metadata lock on table being altered led to deadlock, since it had to wait for ALTER TABLE to release SNW lock. This deadlock was not detected and got resolved only after timeout expiring because waiting were happening in two different subsystems. Similar deadlocks could have occured in other situations. This patch tries to solve the problem by changing ALTER TABLE implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ. After this step handler::external_lock() is called with F_RDLCK as an argument and InnoDB engine correctly interprets ALTER TABLE as operation which only reads data from original version of table. Thanks to this ALTER TABLE acquires only LOCK_S locks on rows it reads. This, in its turn, causes inter-subsystem deadlocks to go away, as all potential lock conflicts and thus deadlocks will be limited to metadata locking subsystem: - When ALTER TABLE reads rows from table being altered it can't encounter any locks which conflict with LOCK_S row locks. There should be no concurrent transactions holding LOCK_X row locks. Such a transaction should have been acquired SW metadata lock on table first which would have conflicted with ALTER's SNW lock. - Vice versa, when DML which runs concurrently with ALTER TABLE tries to lock row it should be requesting only LOCK_S lock which is compatible with locks acquired by ALTER, as otherwise such DML must own an SW metadata lock on table which would be incompatible with ALTER's SNW lock. mysql-test/r/innodb_mysql_lock2.result: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/suite/rpl_ndb/t/rpl_ndb_binlog_format_errors.test: Since CREATE TRIGGER no longer acquires write lock on table it is no longer interpreted as an operation which modifies table data and therefore no longer fails if invoked for SBR-only engine in ROW mode. mysql-test/t/innodb_mysql_lock2.test: Added test for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". sql/ha_partition.cc: When ALTER TABLE creates a new partition to be filled from other partition lock it in F_WRLCK mode instead of using mode which was used for locking the whole table (it is F_RDLCK now). sql/lock.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/mdl.cc: Updated outdated comment to reflect current situation. sql/sql_base.cc: Replaced conditions which used TL_WRITE_ALLOW_READ lock type with equivalent conditions using TL_WRITE_ALLOW_WRITE. This should allow to get rid of TL_WRITE_ALLOW_READ lock type eventually. sql/sql_table.cc: mysql_admin_table(): Use TL_WRITE_ALLOW_WRITE lock type instead of TL_WRITE_ALLOW_READ to determine that we need to acquire upgradable metadata lock. This should allow to completely get rid of TL_WRITE_ALLOW_READ in long term. mysql_recreate_table(): ALTER TABLE now requires TL_READ_NO_INSERT thr_lock.c lock instead of TL_WRITE_ALLOW_READ. sql/sql_trigger.cc: Changed CREATE/DROP TRIGGER implementation to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. The latter is no longer necessary since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement does not change any data in table so there is no need to inform storage engine about it. sql/sql_yacc.yy: Changed implementation of ALTER TABLE (and CREATE/DROP INDEX as a consequence) to use TL_READ_NO_INSERT lock instead of TL_WRITE_ALLOW_READ lock. This is possible since: a) We now can rely on metadata locks to achieve proper isolation between two DDL statements or DDL and DML statements. b) This statement only reads data in table being open. We write data only to the new version of table and then replace with it old version of table under X metadata lock. Thanks to this change InnoDB will no longer acquire LOCK_X locks on rows being read by ALTER TABLE (instead LOCK_S locks will be acquired) and thus cause of bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION" is removed. Did the similar change for CREATE TRIGGER (see comments for sql_trigger.cc for details).
2010-05-26 14:18:08 +02:00
--source include/wait_condition.inc
--echo # The below statement should succeed as transaction
--echo # has SR metadata lock on t1 and only going to read
--echo # rows from it.
insert into t2 select count(*) from t1;
--echo # Unblock ALTER TABLE.
commit;
connection con1;
--echo # Reaping ALTER TABLE.
--reap
connection default;
disconnect con1;
--echo # Clean-up.
drop tables t1, t2;
Committing on behalf or Dmitry Lenev: Fix for bug #46947 "Embedded SELECT without FOR UPDATE is causing a lock", with after-review fixes. SELECT statements with subqueries referencing InnoDB tables were acquiring shared locks on rows in these tables when they were executed in REPEATABLE-READ mode and with statement or mixed mode binary logging turned on. This was a regression which were introduced when fixing bug 39843. The problem was that for tables belonging to subqueries parser set TL_READ_DEFAULT as a lock type. In cases when statement/mixed binary logging at open_tables() time this type of lock was converted to TL_READ_NO_INSERT lock at open_tables() time and caused InnoDB engine to acquire shared locks on reads from these tables. Although in some cases such behavior was correct (e.g. for subqueries in DELETE) in case of SELECT it has caused unnecessary locking. This patch tries to solve this problem by rethinking our approach to how we handle locking for SELECT and subqueries. Now we always set TL_READ_DEFAULT lock type for all cases when we read data. When at open_tables() time this lock is interpreted as TL_READ_NO_INSERT or TL_READ depending on whether this statement as a whole or call to function which uses particular table should be written to the binary log or not (if yes then statement should be properly serialized with concurrent statements and stronger lock should be acquired). Test coverage is added for both InnoDB and MyISAM. This patch introduces an "incompatible" change in locking scheme for subqueries used in SELECT ... FOR UPDATE and SELECT .. IN SHARE MODE. In 4.1 the server would use a snapshot InnoDB read for subqueries in SELECT FOR UPDATE and SELECT .. IN SHARE MODE statements, regardless of whether the binary log is on or off. If the user required a different type of read (i.e. locking read), he/she could request so explicitly by providing FOR UPDATE/IN SHARE MODE clause for each individual subquery. On of the patches for 5.0 broke this behaviour (which was not documented or tested), and started to use locking reads fora all subqueries in SELECT ... FOR UPDATE/IN SHARE MODE. This patch restored 4.1 behaviour. mysql-test/include/check_concurrent_insert.inc: Added auxiliary script which allows to check if statement reading table allows concurrent inserts in it. mysql-test/include/check_no_concurrent_insert.inc: Added auxiliary script which allows to check that statement reading table doesn't allow concurrent inserts in it. mysql-test/include/check_no_row_lock.inc: Added auxiliary script which allows to check if statement reading table doesn't take locks on its rows. mysql-test/include/check_shared_row_lock.inc: Added auxiliary script which allows to check if statement reading table takes shared locks on some of its rows. mysql-test/r/bug39022.result: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/r/innodb_mysql_lock2.result: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/r/lock_sync.result: Added coverage for handling of locking in various cases when we read data from MyISAM tables. mysql-test/t/bug39022.test: After bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock' was fixed test case for bug 39022 has to be adjusted in order to trigger execution path on which original problem was encountered. mysql-test/t/innodb_mysql_lock2.test: Added coverage for handling of locking in various cases when we read data from InnoDB tables (includes test case for bug #46947 'Embedded SELECT without FOR UPDATE is causing a lock'). mysql-test/t/lock_sync.test: Added coverage for handling of locking in various cases when we read data from MyISAM tables. sql/log_event.cc: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/log_event.h: Since LEX::lock_option member was removed we no longer can rely on its value in Load_log_event::print_query() to determine that log event correponds to LOAD DATA CONCURRENT statement (this was not correct in all situations anyway). A new Load_log_event's member was introduced as a replacement. It is initialized at event object construction time and explicitly indicates whether LOAD DATA was concurrent. sql/sp_head.cc: sp_head::reset_lex(): Before parsing substatement reset part of parser state which needs this (e.g. set Yacc_state::m_lock_type to default value). sql/sql_acl.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_base.cc: Changed read_lock_type_for_table() to return a weak TL_READ type of lock in cases when we are executing statement which won't update tables directly and table doesn't belong to statement's prelocking list and thus can't be used by a stored function. It is OK to do so since in this case table won't be used by statement or function call which will be written to the binary log, so serializability requirements for it can be relaxed. One of results from this change is that SELECTs on InnoDB tables no longer takes shared row locks for tables which are used in subqueries (i.e. bug #46947 is fixed). Another result is that for similar SELECTs on MyISAM tables concurrent inserts are allowed. In order to implement this change signature of read_lock_type_for_table() function was changed to take pointers to Query_tables_list and TABLE_LIST objects. sql/sql_base.h: - Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_lex.cc: - Removed LEX::lock_option and st_select_lex::lock_option members. Places in parser that were using them now use Yacc_state::m_lock_type instead. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. It is now reset by Query_tables_list::reset_query_tables_list() method. sql/sql_lex.h: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - To emphasize that LEX::sql_command member is used during process of opening and locking of tables it was moved to Query_tables_list class. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. sql/sql_load.cc: Load_log_event constructor now requires a parameter that indicates whether LOAD DATA is concurrent. sql/sql_parse.cc: LEX::lock_option was replaced with Yacc_state::m_lock_type. And instead of resetting the latter implicitly in mysql_init_multi_delete() we do it explicitly in the places in parser which call this function. sql/sql_priv.h: - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method added flag for HIGH_PRIORITY option. sql/sql_select.cc: Changed code not to rely on LEX::lock_option to determine that it is high-priority SELECT. It was replaced with Yacc_state::m_lock_type which is accessible only at parse time. So instead of LEX::lock_option we now rely on a newly introduced flag for st_select_lex::options - SELECT_HIGH_PRIORITY. sql/sql_show.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed. sql/sql_table.cc: Since LEX::reset_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore value of this member when this method is called by mysql_admin_table(), to make this code safe for re-execution. sql/sql_trigger.cc: Since LEX::reset_n_backup_query_tables_list() now also resets LEX::sql_command member (as it became part of Query_tables_list class) we have to restore it in cases when while working with proxy Query_table_list we assume that LEX::sql_command still corresponds to original SQL command being executed (for example, when we are logging statement to the binary log while having Query_tables_list reset and backed up). sql/sql_update.cc: Function read_lock_type_for_table() now takes pointers to Query_tables_list and TABLE_LIST elements as its arguments since to correctly determine lock type it needs to know what statement is being performed and whether table element for which lock type to be determined belongs to prelocking list. sql/sql_yacc.yy: - Removed st_select_lex::lock_option member as there is no real need for per-SELECT lock type (HIGH_PRIORITY option should apply to the whole statement. FOR UPDATE/LOCK IN SHARE MODE clauses can be handled without this member). The main effect which was achieved by introduction of this member, i.e. using TL_READ_DEFAULT lock type for subqueries, is now achieved by setting LEX::lock_option (or rather its replacement - Yacc_state::m_lock_type) to TL_READ_DEFAULT in almost all cases. - Replaced LEX::lock_option with Yacc_state::m_lock_type in order to emphasize that this value is relevant only during parsing. Unlike for LEX::lock_option the default value for Yacc_state::m_lock_type is TL_READ_DEFAULT. Note that for cases when it is OK to take a "weak" read lock (e.g. simple SELECT) this lock type will be converted to TL_READ at open_tables() time. So this change won't cause negative change in behavior for such statements. OTOH this change ensures that, for example, for SELECTs which are used in stored functions TL_READ_NO_INSERT lock is taken when necessary and as result calls to such stored functions can be written to the binary log with correct serialization. - To be able more easily distinguish high-priority SELECTs in st_select_lex::print() method we now use new flag in st_select_lex::options bit-field.
2010-04-28 12:04:11 +02:00
# Check that all connections opened by test cases in this file are really
# gone so execution of other tests won't be affected by their presence.
--source include/wait_until_count_sessions.inc