mariadb/mysql-test/t/flush_block_commit.test

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# Let's see if FLUSH TABLES WITH READ LOCK blocks COMMIT of existing
# transactions.
# We verify that we did not introduce a deadlock.
# This is intended to mimick how mysqldump and innobackup work.
# And it requires InnoDB
--source include/have_innodb.inc
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
--echo # Save the initial number of concurrent sessions
--source include/count_sessions.inc
--echo # Establish connection con1 (user=root)
connect (con1,localhost,root,,);
--echo # Establish connection con2 (user=root)
connect (con2,localhost,root,,);
--echo # Establish connection con3 (user=root)
connect (con3,localhost,root,,);
--echo # Switch to connection con1
connection con1;
--disable_warnings
DROP TABLE IF EXISTS t1;
--enable_warnings
CREATE TABLE t1 (a INT) ENGINE=innodb;
# blocks COMMIT ?
BEGIN;
INSERT INTO t1 VALUES(1);
--echo # Switch to connection con2
connection con2;
Backport of: ------------------------------------------------------------ revno: 2617.68.10 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-next-bg46673 timestamp: Tue 2009-09-01 19:57:05 +0400 message: Fix for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". Deadlocks occured when one concurrently executed transactions with several statements modifying data and FLUSH TABLES WITH READ LOCK statement or SET READ_ONLY=1 statement. These deadlocks were introduced by the patch for WL 4284: "Transactional DDL locking"/Bug 989: "If DROP TABLE while there's an active transaction, wrong binlog order" which has changed FLUSH TABLES WITH READ LOCK/SET READ_ONLY=1 to wait for pending transactions. What happened was that FLUSH TABLES WITH READ LOCK blocked all further statements changing tables by setting global_read_lock global variable and has started waiting for all pending transactions to complete. Then one of those transactions tried to executed DML, detected that global_read_lock non-zero and tried to wait until global read lock will be released (i.e. global_read_lock becomes 0), indeed, this led to a deadlock. Proper solution for this problem should probably involve full integration of global read lock with metadata locking subsystem (which will allow to implement waiting for pending transactions without blocking DML in them). But since it requires significant changes another, short-term solution for the problem is implemented in this patch. Basically, this patch restores behavior of FLUSH TABLES WITH READ LOCK/ SET READ_ONLY=1 before the patch for WL 4284/bug 989. By ensuring that extra references to TABLE_SHARE are not stored for active metadata locks it changes these statements not to wait for pending transactions. As result deadlock is eliminated. Note that this does not change the fact that active FLUSH TABLES WITH READ LOCK lock or SET READ_ONLY=1 prevent modifications to tables as they also block transaction commits. mysql-test/r/flush_block_commit.result: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/r/mdl_sync.result: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/r/read_only_innodb.result: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. mysql-test/t/flush_block_commit.test: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/t/mdl_sync.test: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/t/read_only_innodb.test: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. sql/sql_base.cc: Disable caching of pointers to TABLE_SHARE objects in MDL subsystem. This means that transactions holding metadata lock on the table will no longer have extra reference to the TABLE_SHARE (due to this lock) and will no longer block concurrent FLUSH TABLES/FLUSH TABLES WITH READ LOCK. Note that this does not change the fact that FLUSH TABLES WITH READ LOCK prevents concurrent transactions from modifying data as it also blocks all commits.
2009-12-09 16:56:34 +01:00
FLUSH TABLES WITH READ LOCK;
--echo # Switch to connection con1
connection con1;
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
--echo # Sending:
Backport of: ------------------------------------------------------------ revno: 2617.68.10 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-next-bg46673 timestamp: Tue 2009-09-01 19:57:05 +0400 message: Fix for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". Deadlocks occured when one concurrently executed transactions with several statements modifying data and FLUSH TABLES WITH READ LOCK statement or SET READ_ONLY=1 statement. These deadlocks were introduced by the patch for WL 4284: "Transactional DDL locking"/Bug 989: "If DROP TABLE while there's an active transaction, wrong binlog order" which has changed FLUSH TABLES WITH READ LOCK/SET READ_ONLY=1 to wait for pending transactions. What happened was that FLUSH TABLES WITH READ LOCK blocked all further statements changing tables by setting global_read_lock global variable and has started waiting for all pending transactions to complete. Then one of those transactions tried to executed DML, detected that global_read_lock non-zero and tried to wait until global read lock will be released (i.e. global_read_lock becomes 0), indeed, this led to a deadlock. Proper solution for this problem should probably involve full integration of global read lock with metadata locking subsystem (which will allow to implement waiting for pending transactions without blocking DML in them). But since it requires significant changes another, short-term solution for the problem is implemented in this patch. Basically, this patch restores behavior of FLUSH TABLES WITH READ LOCK/ SET READ_ONLY=1 before the patch for WL 4284/bug 989. By ensuring that extra references to TABLE_SHARE are not stored for active metadata locks it changes these statements not to wait for pending transactions. As result deadlock is eliminated. Note that this does not change the fact that active FLUSH TABLES WITH READ LOCK lock or SET READ_ONLY=1 prevent modifications to tables as they also block transaction commits. mysql-test/r/flush_block_commit.result: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/r/mdl_sync.result: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/r/read_only_innodb.result: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. mysql-test/t/flush_block_commit.test: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/t/mdl_sync.test: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/t/read_only_innodb.test: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. sql/sql_base.cc: Disable caching of pointers to TABLE_SHARE objects in MDL subsystem. This means that transactions holding metadata lock on the table will no longer have extra reference to the TABLE_SHARE (due to this lock) and will no longer block concurrent FLUSH TABLES/FLUSH TABLES WITH READ LOCK. Note that this does not change the fact that FLUSH TABLES WITH READ LOCK prevents concurrent transactions from modifying data as it also blocks all commits.
2009-12-09 16:56:34 +01:00
--send COMMIT
--echo # Switch to connection con2
connection con2;
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
--echo # Wait until COMMIT gets blocked.
Backport of: ------------------------------------------------------------ revno: 2617.68.10 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-next-bg46673 timestamp: Tue 2009-09-01 19:57:05 +0400 message: Fix for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". Deadlocks occured when one concurrently executed transactions with several statements modifying data and FLUSH TABLES WITH READ LOCK statement or SET READ_ONLY=1 statement. These deadlocks were introduced by the patch for WL 4284: "Transactional DDL locking"/Bug 989: "If DROP TABLE while there's an active transaction, wrong binlog order" which has changed FLUSH TABLES WITH READ LOCK/SET READ_ONLY=1 to wait for pending transactions. What happened was that FLUSH TABLES WITH READ LOCK blocked all further statements changing tables by setting global_read_lock global variable and has started waiting for all pending transactions to complete. Then one of those transactions tried to executed DML, detected that global_read_lock non-zero and tried to wait until global read lock will be released (i.e. global_read_lock becomes 0), indeed, this led to a deadlock. Proper solution for this problem should probably involve full integration of global read lock with metadata locking subsystem (which will allow to implement waiting for pending transactions without blocking DML in them). But since it requires significant changes another, short-term solution for the problem is implemented in this patch. Basically, this patch restores behavior of FLUSH TABLES WITH READ LOCK/ SET READ_ONLY=1 before the patch for WL 4284/bug 989. By ensuring that extra references to TABLE_SHARE are not stored for active metadata locks it changes these statements not to wait for pending transactions. As result deadlock is eliminated. Note that this does not change the fact that active FLUSH TABLES WITH READ LOCK lock or SET READ_ONLY=1 prevent modifications to tables as they also block transaction commits. mysql-test/r/flush_block_commit.result: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/r/mdl_sync.result: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/r/read_only_innodb.result: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. mysql-test/t/flush_block_commit.test: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/t/mdl_sync.test: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/t/read_only_innodb.test: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. sql/sql_base.cc: Disable caching of pointers to TABLE_SHARE objects in MDL subsystem. This means that transactions holding metadata lock on the table will no longer have extra reference to the TABLE_SHARE (due to this lock) and will no longer block concurrent FLUSH TABLES/FLUSH TABLES WITH READ LOCK. Note that this does not change the fact that FLUSH TABLES WITH READ LOCK prevents concurrent transactions from modifying data as it also blocks all commits.
2009-12-09 16:56:34 +01:00
let $wait_condition=
select count(*) = 1 from information_schema.processlist
Patch that refactors global read lock implementation and fixes bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK" and bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'". The first bug manifested itself as a deadlock which occurred when a connection, which had some table open through HANDLER statement, tried to update some data through DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently. What happened was that FTWRL in the second connection managed to perform first step of GRL acquisition and thus blocked all upcoming DML. After that it started to wait for table open through HANDLER statement to be flushed. When the first connection tried to execute DML it has started to wait for GRL/the second connection creating deadlock. The second bug manifested itself as starvation of FLUSH TABLES WITH READ LOCK statements in cases when there was a constant stream of concurrent DML statements (in two or more connections). This has happened because requests for protection against GRL which were acquired by DML statements were ignoring presence of pending GRL and thus the latter was starved. This patch solves both these problems by re-implementing GRL using metadata locks. Similar to the old implementation acquisition of GRL in new implementation is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. The first problem is solved because waits for GRL become visible to deadlock detector in metadata locking subsystem and thus deadlocks like one in the first bug become impossible. The second problem is solved because global S locks which are used for GRL implementation are given preference over IX locks which are acquired by concurrent DML (and we can switch to fair scheduling in future if needed). Important change: FTWRL/GRL no longer blocks DML and DDL on temporary tables. Before this patch behavior was not consistent in this respect: in some cases DML/DDL statements on temporary tables were blocked while in others they were not. Since the main use cases for FTWRL are various forms of backups and temporary tables are not preserved during backups we have opted for consistently allowing DML/DDL on temporary tables during FTWRL/GRL. Important change: This patch changes thread state names which are used when DML/DDL of FTWRL is waiting for global read lock. It is now either "Waiting for global read lock" or "Waiting for commit lock" depending on the stage on which FTWRL is. Incompatible change: To solve deadlock in events code which was exposed by this patch we have to replace LOCK_event_metadata mutex with metadata locks on events. As result we have to prohibit DDL on events under LOCK TABLES. This patch also adds extensive test coverage for interaction of DML/DDL and FTWRL. Performance of new and old global read lock implementations in sysbench tests were compared. There were no significant difference between new and old implementations. mysql-test/include/check_ftwrl_compatible.inc: Added helper script which allows to check that a statement is compatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/check_ftwrl_incompatible.inc: Added helper script which allows to check that a statement is incompatible with FLUSH TABLES WITH READ LOCK. mysql-test/include/handler.inc: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/include/wait_show_condition.inc: Fixed small error in the timeout message. The correct name of variable used as parameter for this script is "$condition" and not "$wait_condition". mysql-test/r/delayed.result: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/r/events_2.result: Updated test results after prohibiting event DDL operations under LOCK TABLES. mysql-test/r/flush.result: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/r/flush_read_lock.result: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/r/flush_read_lock_kill.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/r/handler_innodb.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/handler_myisam.result: Adjusted test case to the fact that now DROP TABLE closes open HANDLERs for the table to be dropped before checking if there active FTWRL in this connection. mysql-test/r/mdl_sync.result: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Updated test results after removing global COND_global_read_lock condition variable. mysql-test/suite/perfschema/r/func_file_io.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/func_mutex.result: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/r/global_read_lock.result: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/r/server_init.result: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/perfschema/t/func_file_io.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/func_mutex.test: Ensure that this test doesn't affect subsequent tests. At the end of its execution enable back P_S instrumentation which this test disables at some point. mysql-test/suite/perfschema/t/global_read_lock.test: Adjusted test case to take into account that new GRL implementation is based on MDL. mysql-test/suite/perfschema/t/server_init.test: Adjusted test case after replacing custom global read lock implementation with one based on MDL and replacing LOCK_event_metadata mutex with metadata lock. mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result: Updated test results after prohibiting event DDL under LOCK TABLES. mysql-test/t/delayed.test: Added test coverage for scenario which triggered assert in metadata locking subsystem. mysql-test/t/events_2.test: Updated test case after prohibiting event DDL operations under LOCK TABLES. mysql-test/t/flush.test: Added test coverage for bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". mysql-test/t/flush_block_commit.test: Adjusted test case after changing thread state name which is used when COMMIT waits for FLUSH TABLES WITH READ LOCK from "Waiting for release of readlock" to "Waiting for commit lock". mysql-test/t/flush_block_commit_notembedded.test: Adjusted test case after changing thread state name which is used when DML waits for FLUSH TABLES WITH READ LOCK. Now we use "Waiting for global read lock" in this case. mysql-test/t/flush_read_lock.test: Added test coverage for various aspects of FLUSH TABLES WITH READ LOCK functionality. mysql-test/t/flush_read_lock_kill-master.opt: We no longer need to use make_global_read_lock_block_commit_loop debug tag in this test. Instead we rely on an appropriate debug_sync point in MDL code. mysql-test/t/flush_read_lock_kill.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Use new debug_sync point. Do not disable concurrent inserts as now InnoDB we always use InnoDB table. mysql-test/t/lock_multi.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". mysql-test/t/mdl_sync.test: Adjusted test case after replacing custom global read lock implementation with one based on metadata locks. Replaced usage of GRL-specific debug_sync's with appropriate sync points in MDL subsystem. Updated thread state names which are used when DDL waits for FTWRL. mysql-test/t/trigger_notembedded.test: Adjusted test case after changing thread state names which are used when DML or DDL waits for FLUSH TABLES WITH READ LOCK to "Waiting for global read lock". sql/event_data_objects.cc: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_data_objects.h: Removed Event_queue_element::status/last_executed_changed members and Event_queue_element::update_timing_fields() method. We no longer use this class for updating mysql.events once event is chosen for execution. Accesses to instances of this class in scheduler thread require protection by Event_queue::LOCK_event_queue mutex and we try to avoid updating table while holding this lock. sql/event_db_repository.cc: - Changed Event_db_repository methods to not release all metadata locks once they are done updating mysql.events table. This allows to keep metadata lock protecting against GRL and lock protecting particular event around until corresponding DDL statement is written to the binary log. - Removed logic for conditional update of "status" and "last_executed" fields from update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" is too much hassle. sql/event_db_repository.h: Removed logic for conditional update of "status" and "last_executed" fields from Event_db_repository:: update_timing_fields_for_event() method. In the only case when this method is called now "last_executed" is always modified and tracking change of "status" field is too much hassle. sql/event_queue.cc: Changed event scheduler code not to update mysql.events table while holding Event_queue::LOCK_event_queue mutex. Doing so led to a deadlock with a new GRL implementation. This deadlock didn't occur with old implementation due to fact that code acquiring protection against GRL ignored pending GRL requests (which lead to GRL starvation). One of goals of new implementation is to disallow GRL starvation and so we have to solve problem with this deadlock in a different way. sql/events.cc: Changed methods of Events class to acquire protection against GRL while perfoming DDL statement and keep it until statement is written to the binary log. Unfortunately this step together with new GRL implementation exposed deadlock involving Events::LOCK_event_metadata and GRL. To solve it Events::LOCK_event_metadata mutex was replaced with a metadata lock on event. As a side-effect events DDL has to be prohibited under LOCK TABLES even in cases when mysql.events table was explicitly locked for write. sql/events.h: Replaced Events::LOCK_event_metadata mutex with a metadata lock on event. sql/ha_ndbcluster.cc: Updated code after replacing custom global read lock implementation with one based on MDL. Since MDL subsystem should now be able to detect deadlocks involving metadata locks and GRL there is no need for special handling of active GRL. sql/handler.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. sql/lock.cc: Replaced custom implementation of global read lock with one based on metadata locks. This step allows to expose wait for GRL to deadlock detector of MDL subsystem and thus succesfully resolve deadlocks similar to one behind bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ LOCK". It also solves problem with GRL starvation described in bug #54673 "It takes too long to get readlock for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used by GRL give preference to FTWRL statement instead of DML statements (if needed in future this can be changed to fair scheduling). Similar to old implementation of acquisition of GRL is two-step. During the first step we block all concurrent DML and DDL statements by acquiring global S metadata lock (each DML and DDL statement acquires global IX lock for its duration). During the second step we block commits by acquiring global S lock in COMMIT namespace (commit code acquires global IX lock in this namespace). Note that unlike in old implementation acquisition of protection against GRL in DML and DDL is semi-automatic. We assume that any statement which should be blocked by GRL will either open and acquires write-lock on tables or acquires metadata locks on objects it is going to modify. For any such statement global IX metadata lock is automatically acquired for its duration. To support this change: - Global_read_lock::lock/unlock_global_read_lock and make_global_read_lock_block_commit methods were changed accordingly. - Global_read_lock::wait_if_global_read_lock() and start_waiting_global_read_lock() methods were dropped. It is now responsibility of code acquiring metadata locks opening tables to acquire protection against GRL by explicitly taking global IX lock with statement duration. - Global variables, mutex and condition variable used by old implementation was removed. - lock_routine_name() was changed to use statement duration for its global IX lock. It was also renamed to lock_object_name() as it now also used to take metadata locks on events. - Global_read_lock::set_explicit_lock_duration() was added which allows not to release locks used for GRL when leaving prelocked mode. sql/lock.h: - Renamed lock_routine_name() to lock_object_name() and changed its signature to allow its usage for events. - Removed broadcast_refresh() function. It is no longer needed with new GRL implementation. sql/log_event.cc: Release metadata locks with statement duration at the end of processing legacy event for LOAD DATA. This ensures that replication thread processing such event properly releases its protection against global read lock. sql/mdl.cc: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Changed thread state name for GLOBAL namespace to "Waiting for global read lock". Optimized MDL_map::find_or_insert() method to avoid taking m_mutex mutex when looking up MDL_lock objects for GLOBAL or COMMIT namespaces. We keep pre-created MDL_lock objects for these namespaces around and simply return pointers to these global objects when needed. Changed MDL_lock/MDL_scoped_lock to properly handle notification of insert delayed handler threads when FTWRL takes global S lock. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mdl.h: Changed MDL subsystem to support new MDL-based implementation of global read lock. Added COMMIT and EVENTS namespaces for metadata locks. Introduced concept of lock duration. In addition to locks with transaction duration which work in the way which is similar to how locks worked before (i.e. they are released at the end of transaction), locks with statement and explicit duration were introduced. Locks with statement duration are automatically released at the end of statement. Locks with explicit duration require explicit release and obsolete concept of transactional sentinel. * Changed MDL_request and MDL_ticket classes to support notion of duration. * Changed MDL_context to keep locks with different duration in different lists. Changed code handling ticket list to take this into account. * Changed methods responsible for releasing locks to take into account duration of tickets. Particularly public MDL_context::release_lock() method now only can release tickets with explicit duration (there is still internal method which allows to specify duration). To release locks with statement or transaction duration one have to use release_statement/transactional_locks() methods. * Concept of savepoint for MDL subsystem now has to take into account locks with statement duration. Consequently MDL_savepoint class was introduced and methods working with savepoints were updated accordingly. * Added methods which allow to set duration for one or all locks in the context. sql/mysqld.cc: Removed global mutex and condition variables which were used by old implementation of GRL. Also we no longer need to initialize Events::LOCK_event_metadata mutex as it was replaced with metadata locks on events. sql/mysqld.h: Removed global variable, mutex and condition variables which were used by old implementation of GRL. sql/rpl_rli.cc: When slave thread closes tables which were open for handling of RBR events ensure that it releases global IX lock which was acquired as protection against GRL. sql/sp.cc: Adjusted code to the new signature of lock_object/routine_name(), to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sp_head.cc: Ensure that statements in stored procedures release statement metadata locks and thus release their protectiong against GRL in proper moment in time. Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_admin.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_base.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. Code doing this also responsible for checking that current connection has no active GRL by calling an Global_read_lock::can_acquire_protection() method. Changed code in open_table() and lock_table_names() accordingly. Note that as result of this change DDL and DML on temporary tables is always compatible with GRL (before it was incompatible in some cases and compatible in other cases). - To speed-up code acquiring protection against GRL introduced m_has_protection_against_grl member in Open_table_context class. It indicates that protection was already acquired sometime during open_tables() execution and new attempts can be skipped. - Thanks to new GRL implementation calls to broadcast_refresh() became unnecessary and were removed. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_base.h: Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. Also introduced Open_table_context::m_has_protection_against_grl member which allows to avoid acquiring protection against GRL while opening tables if such protection was already acquired. sql/sql_class.cc: Changed THD::leave_locked_tables_mode() after transactional sentinel for metadata locks was obsoleted by introduction of locks with explicit duration. sql/sql_class.h: - Adjusted code to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. - Changed Global_read_lock class according to changes in global read lock implementation: * wait_if_global_read_lock and start_waiting_global_read_lock are now gone. Instead code needing protection against GRL has to acquire global IX metadata lock with statement duration itself. To help it new can_acquire_protection() was introduced. Also as result of the above change m_protection_count member is gone too. * Added m_mdl_blocks_commits_lock member to store metadata lock blocking commits. * Adjusted code to the fact that concept of transactional sentinel was obsoleted by concept of lock duration. - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer necessary. New GRL implementation acquires protection against global read lock automagically when statement acquires metadata locks on tables or other objects it is going to change. sql/sql_db.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/sql_handler.cc: Removed call to broadcast_refresh() function. It is no longer needed with new GRL implementation. Adjusted code after introducing duration concept for metadata locks. Particularly to the fact transactional sentinel was replaced with explicit duration. sql/sql_handler.h: Renamed mysql_ha_move_tickets_after_trans_sentinel() to mysql_ha_set_explicit_lock_duration() after transactional sentinel was obsoleted by locks with explicit duration. sql/sql_insert.cc: Adjusted code handling delaying inserts after switching to new GRL implementation. Now connection thread initiating delayed insert has to acquire global IX lock in addition to metadata lock on table being inserted into. This IX lock protects against GRL and similarly to SW lock on table being inserted into has to be passed to handler thread in order to avoid deadlocks. sql/sql_lex.cc: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_lex.h: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/sql_parse.cc: - Implemented support for new approach to acquiring protection against global read lock. We no longer acquire such protection explicitly on the basis of statement flags. Instead we always rely on code which is responsible for acquiring metadata locks on object to be changed acquiring this protection. This is achieved by acquiring global IX metadata lock with statement duration. This lock is automatically released at the end of statement execution. - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not to release metadata locks and thus protection against of GRL in the middle of statement execution. - Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_prepare.cc: Adjusted code to the to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_rename.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before renaming tables. This happens automatically in code which acquires metadata locks on tables being renamed. sql/sql_show.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request and to the fact that savepoints for MDL subsystem are now represented by MDL_savepoint class. sql/sql_table.cc: - With new GRL implementation there is no need to explicitly acquire protection against GRL before dropping tables. This happens automatically in code which acquires metadata locks on tables being dropped. - Changed mysql_alter_table() not to release lock on new table name explicitly and to rely on automatic release of locks at the end of statement instead. This was necessary since now MDL_context::release_lock() is supported only for locks for explicit duration. sql/sql_trigger.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before changing table triggers. This happens automatically in code which acquires metadata locks on tables which triggers are to be changed. sql/sql_update.cc: Fix bug exposed by GRL testing. During prepare phase acquire only S metadata locks instead of SW locks to keep prepare of multi-UPDATE compatible with concurrent LOCK TABLES WRITE and global read lock. sql/sql_view.cc: With new GRL implementation there is no need to explicitly acquire protection against GRL before creating view. This happens automatically in code which acquires metadata lock on view to be created. sql/sql_yacc.yy: LEX::protect_against_global_read_lock member is no longer necessary since protection against GRL is automatically taken by code acquiring metadata locks/opening tables. sql/table.cc: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/table.h: Adjusted code to the fact that one now needs specify duration of lock when initializing MDL_request. sql/transaction.cc: Replaced custom implementation of global read lock with one based on metadata locks. Consequently when doing commit instead of calling method of Global_read_lock class to acquire protection against GRL we simply acquire IX in COMMIT namespace. Also adjusted code to the fact that MDL savepoint is now represented by MDL_savepoint class.
2010-11-11 18:11:05 +01:00
where state = "Waiting for commit lock" and info = "COMMIT";
Backport of: ------------------------------------------------------------ revno: 2617.68.10 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-next-bg46673 timestamp: Tue 2009-09-01 19:57:05 +0400 message: Fix for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". Deadlocks occured when one concurrently executed transactions with several statements modifying data and FLUSH TABLES WITH READ LOCK statement or SET READ_ONLY=1 statement. These deadlocks were introduced by the patch for WL 4284: "Transactional DDL locking"/Bug 989: "If DROP TABLE while there's an active transaction, wrong binlog order" which has changed FLUSH TABLES WITH READ LOCK/SET READ_ONLY=1 to wait for pending transactions. What happened was that FLUSH TABLES WITH READ LOCK blocked all further statements changing tables by setting global_read_lock global variable and has started waiting for all pending transactions to complete. Then one of those transactions tried to executed DML, detected that global_read_lock non-zero and tried to wait until global read lock will be released (i.e. global_read_lock becomes 0), indeed, this led to a deadlock. Proper solution for this problem should probably involve full integration of global read lock with metadata locking subsystem (which will allow to implement waiting for pending transactions without blocking DML in them). But since it requires significant changes another, short-term solution for the problem is implemented in this patch. Basically, this patch restores behavior of FLUSH TABLES WITH READ LOCK/ SET READ_ONLY=1 before the patch for WL 4284/bug 989. By ensuring that extra references to TABLE_SHARE are not stored for active metadata locks it changes these statements not to wait for pending transactions. As result deadlock is eliminated. Note that this does not change the fact that active FLUSH TABLES WITH READ LOCK lock or SET READ_ONLY=1 prevent modifications to tables as they also block transaction commits. mysql-test/r/flush_block_commit.result: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/r/mdl_sync.result: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/r/read_only_innodb.result: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. mysql-test/t/flush_block_commit.test: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/t/mdl_sync.test: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/t/read_only_innodb.test: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. sql/sql_base.cc: Disable caching of pointers to TABLE_SHARE objects in MDL subsystem. This means that transactions holding metadata lock on the table will no longer have extra reference to the TABLE_SHARE (due to this lock) and will no longer block concurrent FLUSH TABLES/FLUSH TABLES WITH READ LOCK. Note that this does not change the fact that FLUSH TABLES WITH READ LOCK prevents concurrent transactions from modifying data as it also blocks all commits.
2009-12-09 16:56:34 +01:00
--source include/wait_condition.inc
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
--echo # Verify that 'con1' was blocked and data did not move.
SELECT * FROM t1;
UNLOCK TABLES;
--echo # Switch to connection con1
connection con1;
Backport of: ------------------------------------------------------------ revno: 2617.68.10 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-next-bg46673 timestamp: Tue 2009-09-01 19:57:05 +0400 message: Fix for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". Deadlocks occured when one concurrently executed transactions with several statements modifying data and FLUSH TABLES WITH READ LOCK statement or SET READ_ONLY=1 statement. These deadlocks were introduced by the patch for WL 4284: "Transactional DDL locking"/Bug 989: "If DROP TABLE while there's an active transaction, wrong binlog order" which has changed FLUSH TABLES WITH READ LOCK/SET READ_ONLY=1 to wait for pending transactions. What happened was that FLUSH TABLES WITH READ LOCK blocked all further statements changing tables by setting global_read_lock global variable and has started waiting for all pending transactions to complete. Then one of those transactions tried to executed DML, detected that global_read_lock non-zero and tried to wait until global read lock will be released (i.e. global_read_lock becomes 0), indeed, this led to a deadlock. Proper solution for this problem should probably involve full integration of global read lock with metadata locking subsystem (which will allow to implement waiting for pending transactions without blocking DML in them). But since it requires significant changes another, short-term solution for the problem is implemented in this patch. Basically, this patch restores behavior of FLUSH TABLES WITH READ LOCK/ SET READ_ONLY=1 before the patch for WL 4284/bug 989. By ensuring that extra references to TABLE_SHARE are not stored for active metadata locks it changes these statements not to wait for pending transactions. As result deadlock is eliminated. Note that this does not change the fact that active FLUSH TABLES WITH READ LOCK lock or SET READ_ONLY=1 prevent modifications to tables as they also block transaction commits. mysql-test/r/flush_block_commit.result: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/r/mdl_sync.result: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/r/read_only_innodb.result: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. mysql-test/t/flush_block_commit.test: Adjusted test case after change in FLUSH TABLES WITH READ LOCK behavior - it is no longer blocked by a pending transaction. mysql-test/t/mdl_sync.test: Added test for bug #46673 "Deadlock between FLUSH TABLES WITH READ LOCK and DML". mysql-test/t/read_only_innodb.test: Adjusted test case after change in SET READ_ONLY behavior - it is no longer blocked by a pending transaction. sql/sql_base.cc: Disable caching of pointers to TABLE_SHARE objects in MDL subsystem. This means that transactions holding metadata lock on the table will no longer have extra reference to the TABLE_SHARE (due to this lock) and will no longer block concurrent FLUSH TABLES/FLUSH TABLES WITH READ LOCK. Note that this does not change the fact that FLUSH TABLES WITH READ LOCK prevents concurrent transactions from modifying data as it also blocks all commits.
2009-12-09 16:56:34 +01:00
--echo # Reaping COMMIT
--reap
# No deadlock ?
--echo # Switch to connection con1
connection con1;
BEGIN;
SELECT * FROM t1 FOR UPDATE;
--echo # Switch to connection con2
connection con2;
BEGIN;
send SELECT * FROM t1 FOR UPDATE; # blocked by con1
sleep 1;
--echo # Switch to connection con3
connection con3;
send FLUSH TABLES WITH READ LOCK; # blocked by con2
--echo # Switch to connection con1
connection con1;
COMMIT; # should not be blocked by con3
--echo # Switch to connection con2
connection con2;
reap;
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
COMMIT;
--echo # Switch to connection con3
connection con3;
reap;
UNLOCK TABLES;
# Bug#6732 FLUSH TABLES WITH READ LOCK + COMMIT hangs later FLUSH TABLES
# WITH READ LOCK
--echo # Switch to connection con2
connection con2;
COMMIT; # unlock InnoDB row locks to allow insertions
--echo # Switch to connection con1
connection con1;
BEGIN;
INSERT INTO t1 VALUES(10);
FLUSH TABLES WITH READ LOCK;
--echo # Switch to connection con2
connection con2;
FLUSH TABLES WITH READ LOCK; # bug caused hang here
UNLOCK TABLES;
# Bug#7358 SHOW CREATE DATABASE fails if open transaction
BEGIN;
SELECT * FROM t1;
SHOW CREATE DATABASE test;
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
COMMIT;
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
--echo # Cleanup
--echo # Switch to connection default and close connections con1, con2, con3
connection default;
disconnect con1;
disconnect con2;
disconnect con3;
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
--echo # We commit open transactions when we disconnect: only then we can
--echo # drop the table.
DROP TABLE t1;
--echo # End of 4.1 tests
Backport of revno ## 2617.31.1, 2617.31.3, 2617.31.4, 2617.31.5, 2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1 - initial changeset that introduced the fix for Bug#989 and follow up fixes for all test suite failures introduced in the initial changeset. ------------------------------------------------------------ revno: 2617.31.1 committer: Davi Arnaut <Davi.Arnaut@Sun.COM> branch nick: 4284-6.0 timestamp: Fri 2009-03-06 19:17:00 -0300 message: Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order WL#4284: Transactional DDL locking Currently the MySQL server does not keep metadata locks on schema objects for the duration of a transaction, thus failing to guarantee the integrity of the schema objects being used during the transaction and to protect then from concurrent DDL operations. This also poses a problem for replication as a DDL operation might be replicated even thought there are active transactions using the object being modified. The solution is to defer the release of metadata locks until a active transaction is either committed or rolled back. This prevents other statements from modifying the table for the entire duration of the transaction. This provides commitment ordering for guaranteeing serializability across multiple transactions. - Incompatible change: If MySQL's metadata locking system encounters a lock conflict, the usual schema is to use the try and back-off technique to avoid deadlocks -- this schema consists in releasing all locks and trying to acquire them all in one go. But in a transactional context this algorithm can't be utilized as its not possible to release locks acquired during the course of the transaction without breaking the transaction commitments. To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be returned if a lock conflict is encountered during a transaction. Let's consider an example: A transaction has two statements that modify table t1, then table t2, and then commits. The first statement of the transaction will acquire a shared metadata lock on table t1, and it will be kept utill COMMIT to ensure serializability. At the moment when the second statement attempts to acquire a shared metadata lock on t2, a concurrent ALTER or DROP statement might have locked t2 exclusively. The prescription of the current locking protocol is that the acquirer of the shared lock backs off -- gives up all his current locks and retries. This implies that the entire multi-statement transaction has to be rolled back. - Incompatible change: FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ LOCK won't cause locked tables to be implicitly unlocked anymore. mysql-test/extra/binlog_tests/drop_table.test: Add test case for Bug#989. mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix1.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/include/mix2.inc: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/r/flush_block_commit.result: Update test case result (WL#4284). mysql-test/r/flush_block_commit_notembedded.result: Update test case result (WL#4284). mysql-test/r/innodb.result: Update test case result (WL#4284). mysql-test/r/innodb_mysql.result: Update test case result (WL#4284). mysql-test/r/lock.result: Add test case result for an effect of WL#4284/Bug#989 (all locks should be released when a connection terminates). mysql-test/r/mix2_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/not_embedded_server.result: Update test case result (effects of WL#4284/Bug#989). Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES. mysql-test/r/partition_innodb_semi_consistent.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/r/partition_sync.result: Temporarily disable the test case for Bug#43867, which will be fixed by a subsequent backport. mysql-test/r/ps.result: Add a test case for effect of PREPARE on transactional locks: we take a savepoint at beginning of PREAPRE and release it at the end. Thus PREPARE does not accumulate metadata locks (Bug#989/WL#4284). mysql-test/r/read_only_innodb.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result: Add a test case result (WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result: Update test case result (effects of WL#4284/Bug#989). mysql-test/suite/binlog/r/binlog_unsafe.result: A side effect of Bug#989 -- slightly different table map ids. mysql-test/suite/binlog/t/binlog_row_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test: Add a test case for WL#4284/Bug#989. mysql-test/suite/binlog/t/binlog_stm_row.test: Update to the new state name. This is actually a follow up to another patch for WL#4284, that changes Locked thread state to Table lock. mysql-test/suite/ndb/r/ndb_index_ordered.result: Remove result for disabled part of the test case. mysql-test/suite/ndb/t/disabled.def: Temporarily disable a test case (Bug#45621). mysql-test/suite/ndb/t/ndb_index_ordered.test: Disable a part of a test case (needs update to reflect semantics of Bug#989). mysql-test/suite/rpl/t/disabled.def: Disable tests made meaningless by transactional metadata locking. mysql-test/suite/sys_vars/r/autocommit_func.result: Add a commit (Bug#989). mysql-test/suite/sys_vars/t/autocommit_func.test: Add a commit (Bug#989). mysql-test/t/flush_block_commit.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. mysql-test/t/flush_block_commit_notembedded.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction. Add a test case for transaction-scope locks and the global read lock (Bug#989/WL#4284). mysql-test/t/innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (effects of Bug#989/WL#4284). mysql-test/t/lock.test: Add a test case for Bug#989/WL#4284. mysql-test/t/not_embedded_server.test: Add a test case for Bug#989/WL#4284. mysql-test/t/partition_innodb_semi_consistent.test: Replace TRUNCATE with DELETE, to not issue an implicit commit of a transaction, and not depend on metadata locks. mysql-test/t/partition_sync.test: Temporarily disable the test case for Bug#43867, which needs a fix to be backported from 6.0. mysql-test/t/ps.test: Add a test case for semantics of PREPARE and transaction-scope locks: metadata locks on tables used in PREPARE are enclosed into a temporary savepoint, taken at the beginning of PREPARE, and released at the end. Thus PREPARE does not effect what locks a transaction owns. mysql-test/t/read_only_innodb.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). Wait for the read_only statement to actually flush tables before sending other concurrent statements that depend on its state. mysql-test/t/xa.test: Fix test case to reflect the fact that transactions now hold metadata locks for the duration of a transaction (Bug#989/WL#4284). sql/ha_ndbcluster_binlog.cc: Backport bits of changes of ha_ndbcluster_binlog.cc from 6.0, to fix the failing binlog test suite with WL#4284. WL#4284 implementation does not work with 5.1 implementation of ndbcluster binlog index. sql/log_event.cc: Release metadata locks after issuing a commit. sql/mdl.cc: Style changes (WL#4284). sql/mysql_priv.h: Rename parameter to match the name used in the definition (WL#4284). sql/rpl_injector.cc: Release metadata locks on commit (WL#4284). sql/rpl_rli.cc: Remove assert made meaningless, metadata locks are released at the end of the transaction. sql/set_var.cc: Close tables and release locks if autocommit mode is set. sql/slave.cc: Release metadata locks after a rollback. sql/sql_acl.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_base.cc: Defer the release of metadata locks when closing tables if not required to. Issue a deadlock error if the locking protocol requires that a transaction re-acquire its locks. Release metadata locks when closing tables for reopen. sql/sql_class.cc: Release metadata locks if the thread is killed. sql/sql_parse.cc: Release metadata locks after implicitly committing a active transaction, or after explicit commits or rollbacks. sql/sql_plugin.cc: Allocate MDL request on the stack as the use of the table is contained within the function. It will be removed from the context once close_thread_tables is called at the end of the function. sql/sql_prepare.cc: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. After some discussions with stakeholders it has been decided that metadata locks acquired during a PREPARE statement must be released once the statement is prepared even if it is prepared within a multi statement transaction. sql/sql_servers.cc: Don't implicitly unlock locked tables. Issue a implicit commit at the end and unlock tables. sql/sql_table.cc: Close table and release metadata locks after a admin operation. sql/table.h: The problem is that the prepare phase of the CREATE TABLE statement takes a exclusive metadata lock lock and this can cause a self-deadlock the thread already holds a shared lock on the table being that should be created. The solution is to make the prepare phase take a shared metadata lock when preparing a CREATE TABLE statement. The execution of the statement will still acquire a exclusive lock, but won't cause any problem as it issues a implicit commit. sql/transaction.cc: Release metadata locks after the implicitly committed due to a new transaction being started. Also, release metadata locks acquired after a savepoint if the transaction is rolled back to the save point. The problem is that in some cases transaction-long metadata locks could be released before the transaction was committed. This could happen when a active transaction was ended by a "START TRANSACTION" or "BEGIN" statement, in which case the metadata locks would be released before the actual commit of the active transaction. The solution is to defer the release of metadata locks to after the transaction has been implicitly committed. No test case is provided as the effort to provide one is too disproportional to the size of the fix.
2009-12-05 00:02:48 +01:00
--echo # Wait till all disconnects are completed
--source include/wait_until_count_sessions.inc