mariadb/mysql-test/t/lock.test

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#
# Testing of table locking
#
--disable_warnings
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.
2009-12-05 02:02:48 +03:00
drop table if exists t1,t2,t3;
--enable_warnings
CREATE TABLE t1 ( `id` int(11) NOT NULL default '0', `id2` int(11) NOT NULL default '0', `id3` int(11) NOT NULL default '0', `dummy1` char(30) default NULL, PRIMARY KEY (`id`,`id2`), KEY `index_id3` (`id3`)) ENGINE=MyISAM;
insert into t1 (id,id2) values (1,1),(1,2),(1,3);
LOCK TABLE t1 WRITE;
select dummy1,count(distinct id) from t1 group by dummy1;
update t1 set id=-1 where id=1;
LOCK TABLE t1 READ;
--error 1099
update t1 set id=1 where id=1;
--error 1100
create table t2 SELECT * from t1;
create temporary table t2 SELECT * from t1;
drop table if exists t2;
unlock tables;
create table t2 SELECT * from t1;
LOCK TABLE t1 WRITE,t2 write;
insert into t2 SELECT * from t1;
update t1 set id=1 where id=-1;
drop table t1,t2;
#
# Check bug with INSERT ... SELECT with lock tables
#
CREATE TABLE t1 (
index1 smallint(6) default NULL,
nr smallint(6) default NULL,
KEY index1(index1)
) ENGINE=MyISAM;
CREATE TABLE t2 (
nr smallint(6) default NULL,
name varchar(20) default NULL
) ENGINE=MyISAM;
INSERT INTO t2 VALUES (1,'item1');
INSERT INTO t2 VALUES (2,'item2');
# problem begins here!
lock tables t1 write, t2 read;
insert into t1 select 1,nr from t2 where name='item1';
insert into t1 select 2,nr from t2 where name='item2';
unlock tables;
check table t1;
# Check error message
lock tables t1 write;
check table t2;
--error 1100
insert into t1 select index1,nr from t1;
unlock tables;
lock tables t1 write, t1 as t1_alias read;
insert into t1 select index1,nr from t1 as t1_alias;
--error ER_TABLE_NOT_LOCKED
drop table t1,t2;
unlock tables;
drop table t1,t2;
#
# BUG#5390 - problems with merge tables
# Supplement test for the after-fix optimization
# Check that a dropped table is correctly removed from a lock.
create table t1 (c1 int);
create table t2 (c1 int);
create table t3 (c1 int);
lock tables t1 write, t2 write, t3 write;
# This removes one table after the other from the lock.
drop table t2, t3, t1;
#
# Check that a lock merge works.
create table t1 (c1 int);
create table t2 (c1 int);
create table t3 (c1 int);
lock tables t1 write, t2 write, t3 write, t1 as t4 read;
alter table t2 add column c2 int;
drop table t1, t2, t3;
# Bug7241 - Invalid response when DELETE .. USING and LOCK TABLES used.
#
create table t1 ( a int(11) not null auto_increment, primary key(a));
create table t2 ( a int(11) not null auto_increment, primary key(a));
lock tables t1 write, t2 read;
delete from t1 using t1,t2 where t1.a=t2.a;
delete t1 from t1,t2 where t1.a=t2.a;
--error 1099
delete from t2 using t1,t2 where t1.a=t2.a;
--error 1099
delete t2 from t1,t2 where t1.a=t2.a;
--error ER_TABLE_NOT_LOCKED_FOR_WRITE
drop table t1,t2;
unlock tables;
drop table t2,t1;
BUG#9953: CONVERT_TZ requires mysql.time_zone_name to be locked The problem was that some facilities (like CONVERT_TZ() function or server HELP statement) may require implicit access to some tables in 'mysql' database. This access was done by ordinary means of adding such tables to the list of tables the query is going to open. However, if we issued LOCK TABLES before that, we would get "table was not locked" error trying to open such implicit tables. The solution is to treat certain tables as MySQL system tables, like we already do for mysql.proc. Such tables may be opened for reading at any moment regardless of any locks in effect. The cost of this is that system table may be locked for writing only together with other system tables, it is disallowed to lock system tables for writing and have any other lock on any other table. After this patch the following tables are treated as MySQL system tables: mysql.help_category mysql.help_keyword mysql.help_relation mysql.help_topic mysql.proc (it already was) mysql.time_zone mysql.time_zone_leap_second mysql.time_zone_name mysql.time_zone_transition mysql.time_zone_transition_type These tables are now opened with open_system_tables_for_read() and closed with close_system_tables(), or one table may be opened with open_system_table_for_update() and closed with close_thread_tables() (the latter is used for mysql.proc table, which is updated as part of normal MySQL server operation). These functions may be used when some tables were opened and locked already. NOTE: online update of time zone tables is not possible during replication, because there's no time zone cache flush neither on LOCK TABLES, nor on FLUSH TABLES, so the master may serve stale time zone data from cache, while on slave updated data will be loaded from the time zone tables.
2007-03-09 13:12:31 +03:00
--echo End of 4.1 tests.
#
# Bug#18884 "lock table + global read lock = crash"
# The bug is not repeatable, just add the test case.
#
--disable_warnings
drop table if exists t1;
--enable_warnings
create table t1 (a int);
lock table t1 write;
--error ER_LOCK_OR_ACTIVE_TRANSACTION
flush tables with read lock;
unlock tables;
drop table t1;
BUG#9953: CONVERT_TZ requires mysql.time_zone_name to be locked The problem was that some facilities (like CONVERT_TZ() function or server HELP statement) may require implicit access to some tables in 'mysql' database. This access was done by ordinary means of adding such tables to the list of tables the query is going to open. However, if we issued LOCK TABLES before that, we would get "table was not locked" error trying to open such implicit tables. The solution is to treat certain tables as MySQL system tables, like we already do for mysql.proc. Such tables may be opened for reading at any moment regardless of any locks in effect. The cost of this is that system table may be locked for writing only together with other system tables, it is disallowed to lock system tables for writing and have any other lock on any other table. After this patch the following tables are treated as MySQL system tables: mysql.help_category mysql.help_keyword mysql.help_relation mysql.help_topic mysql.proc (it already was) mysql.time_zone mysql.time_zone_leap_second mysql.time_zone_name mysql.time_zone_transition mysql.time_zone_transition_type These tables are now opened with open_system_tables_for_read() and closed with close_system_tables(), or one table may be opened with open_system_table_for_update() and closed with close_thread_tables() (the latter is used for mysql.proc table, which is updated as part of normal MySQL server operation). These functions may be used when some tables were opened and locked already. NOTE: online update of time zone tables is not possible during replication, because there's no time zone cache flush neither on LOCK TABLES, nor on FLUSH TABLES, so the master may serve stale time zone data from cache, while on slave updated data will be loaded from the time zone tables.
2007-03-09 13:12:31 +03:00
#
# Test LOCK TABLE on system tables. See bug#9953: CONVERT_TZ requires
# mysql.time_zone_name to be locked.
#
--disable_warnings
DROP TABLE IF EXISTS t1;
--enable_warnings
CREATE TABLE t1 (i INT);
LOCK TABLES mysql.time_zone READ, mysql.proc READ, t1 READ;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone READ, mysql.proc READ, t1 WRITE;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone READ, mysql.proc READ;
UNLOCK TABLES;
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE;
UNLOCK TABLES;
# If at least one system table is locked for WRITE, then all other
# tables should be system tables locked also for WRITE.
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
LOCK TABLES mysql.time_zone READ, mysql.proc WRITE, t1 READ;
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE, t1 READ;
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
LOCK TABLES mysql.time_zone WRITE, mysql.proc WRITE, t1 WRITE;
--error ER_WRONG_LOCK_OF_SYSTEM_TABLE
LOCK TABLES mysql.time_zone READ, mysql.proc WRITE;
DROP TABLE t1;
--echo
--echo Bug#5719 impossible to lock VIEW
--echo
--echo Just covering existing behaviour with tests.
--echo Consistency has not been found here.
--echo
--disable_warnings
drop view if exists v_bug5719;
drop table if exists t1, t2, t3;
--enable_warnings
create table t1 (a int);
create temporary table t2 (a int);
create table t3 (a int);
create view v_bug5719 as select 1;
lock table v_bug5719 write;
--error ER_TABLE_NOT_LOCKED
select * from t1;
--echo
--echo Allowed to select from a temporary talbe under LOCK TABLES
--echo
select * from t2;
--error ER_TABLE_NOT_LOCKED
select * from t3;
select * from v_bug5719;
Initial import of WL#3726 "DDL locking for all metadata objects". Backport of: ------------------------------------------------------------ revno: 2630.4.1 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Fri 2008-05-23 17:54:03 +0400 message: WL#3726 "DDL locking for all metadata objects". After review fixes in progress. ------------------------------------------------------------ This is the first patch in series. It transforms the metadata locking subsystem to use a dedicated module (mdl.h,cc). No significant changes in the locking protocol. The import passes the test suite with the exception of deprecated/removed 6.0 features, and MERGE tables. The latter are subject to a fix by WL#4144. Unfortunately, the original changeset comments got lost in a merge, thus this import has its own (largely insufficient) comments. This patch fixes Bug#25144 "replication / binlog with view breaks". Warning: this patch introduces an incompatible change: Under LOCK TABLES, it's no longer possible to FLUSH a table that was not locked for WRITE. Under LOCK TABLES, it's no longer possible to DROP a table or VIEW that was not locked for WRITE. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.2 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 14:03:45 +0400 message: WL#3726 "DDL locking for all metadata objects". After review fixes in progress. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.3 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 14:08:51 +0400 message: WL#3726 "DDL locking for all metadata objects" Fixed failing Windows builds by adding mdl.cc to the lists of files needed to build server/libmysqld on Windows. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.4 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 21:57:58 +0400 message: WL#3726 "DDL locking for all metadata objects". Fix for assert failures in kill.test which occured when one tried to kill ALTER TABLE statement on merge table while it was waiting in wait_while_table_is_used() for other connections to close this table. These assert failures stemmed from the fact that cleanup code in this case assumed that temporary table representing new version of table was open with adding to THD::temporary_tables list while code which were opening this temporary table wasn't always fulfilling this. This patch changes code that opens new version of table to always do this linking in. It also streamlines cleanup process for cases when error occurs while we have new version of table open. ****** WL#3726 "DDL locking for all metadata objects" Add libmysqld/mdl.cc to .bzrignore. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.6 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sun 2008-05-25 00:33:22 +0400 message: WL#3726 "DDL locking for all metadata objects". Addition to the fix of assert failures in kill.test caused by changes for this worklog. Make sure we close the new table only once.
2009-11-30 18:55:03 +03:00
--error ER_LOCK_OR_ACTIVE_TRANSACTION
drop view v_bug5719;
--echo
--echo sic: did not left LOCK TABLES mode automatically
--echo
--error ER_TABLE_NOT_LOCKED
select * from t1;
unlock tables;
Initial import of WL#3726 "DDL locking for all metadata objects". Backport of: ------------------------------------------------------------ revno: 2630.4.1 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Fri 2008-05-23 17:54:03 +0400 message: WL#3726 "DDL locking for all metadata objects". After review fixes in progress. ------------------------------------------------------------ This is the first patch in series. It transforms the metadata locking subsystem to use a dedicated module (mdl.h,cc). No significant changes in the locking protocol. The import passes the test suite with the exception of deprecated/removed 6.0 features, and MERGE tables. The latter are subject to a fix by WL#4144. Unfortunately, the original changeset comments got lost in a merge, thus this import has its own (largely insufficient) comments. This patch fixes Bug#25144 "replication / binlog with view breaks". Warning: this patch introduces an incompatible change: Under LOCK TABLES, it's no longer possible to FLUSH a table that was not locked for WRITE. Under LOCK TABLES, it's no longer possible to DROP a table or VIEW that was not locked for WRITE. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.2 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 14:03:45 +0400 message: WL#3726 "DDL locking for all metadata objects". After review fixes in progress. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.3 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 14:08:51 +0400 message: WL#3726 "DDL locking for all metadata objects" Fixed failing Windows builds by adding mdl.cc to the lists of files needed to build server/libmysqld on Windows. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.4 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sat 2008-05-24 21:57:58 +0400 message: WL#3726 "DDL locking for all metadata objects". Fix for assert failures in kill.test which occured when one tried to kill ALTER TABLE statement on merge table while it was waiting in wait_while_table_is_used() for other connections to close this table. These assert failures stemmed from the fact that cleanup code in this case assumed that temporary table representing new version of table was open with adding to THD::temporary_tables list while code which were opening this temporary table wasn't always fulfilling this. This patch changes code that opens new version of table to always do this linking in. It also streamlines cleanup process for cases when error occurs while we have new version of table open. ****** WL#3726 "DDL locking for all metadata objects" Add libmysqld/mdl.cc to .bzrignore. ****** Backport of: ------------------------------------------------------------ revno: 2630.4.6 committer: Dmitry Lenev <dlenev@mysql.com> branch nick: mysql-6.0-3726-w timestamp: Sun 2008-05-25 00:33:22 +0400 message: WL#3726 "DDL locking for all metadata objects". Addition to the fix of assert failures in kill.test caused by changes for this worklog. Make sure we close the new table only once.
2009-11-30 18:55:03 +03:00
create or replace view v_bug5719 as select * from t1;
lock tables v_bug5719 write;
select * from v_bug5719;
--echo
--echo Allowed to use an underlying table under LOCK TABLES <view>
--echo
select * from t1;
--echo
--echo Allowed to select from a temporary table under LOCK TABLES
--echo
select * from t2;
--error ER_TABLE_NOT_LOCKED
select * from t3;
drop table t1;
--echo
--echo sic: left LOCK TABLES mode
--echo
select * from t3;
--error ER_VIEW_INVALID
select * from v_bug5719;
unlock tables;
drop view v_bug5719;
--echo
--echo When limitation to use temporary tables in views is removed, please
--echo add a test that shows what happens under LOCK TABLES when a view
--echo references a temporary table, is locked, and the underlying table
--echo is dropped.
--echo
--error ER_VIEW_SELECT_TMPTABLE
create view v_bug5719 as select * from t2;
--echo
--echo Cleanup.
--echo
drop table t2, t3;
BUG#9953: CONVERT_TZ requires mysql.time_zone_name to be locked The problem was that some facilities (like CONVERT_TZ() function or server HELP statement) may require implicit access to some tables in 'mysql' database. This access was done by ordinary means of adding such tables to the list of tables the query is going to open. However, if we issued LOCK TABLES before that, we would get "table was not locked" error trying to open such implicit tables. The solution is to treat certain tables as MySQL system tables, like we already do for mysql.proc. Such tables may be opened for reading at any moment regardless of any locks in effect. The cost of this is that system table may be locked for writing only together with other system tables, it is disallowed to lock system tables for writing and have any other lock on any other table. After this patch the following tables are treated as MySQL system tables: mysql.help_category mysql.help_keyword mysql.help_relation mysql.help_topic mysql.proc (it already was) mysql.time_zone mysql.time_zone_leap_second mysql.time_zone_name mysql.time_zone_transition mysql.time_zone_transition_type These tables are now opened with open_system_tables_for_read() and closed with close_system_tables(), or one table may be opened with open_system_table_for_update() and closed with close_thread_tables() (the latter is used for mysql.proc table, which is updated as part of normal MySQL server operation). These functions may be used when some tables were opened and locked already. NOTE: online update of time zone tables is not possible during replication, because there's no time zone cache flush neither on LOCK TABLES, nor on FLUSH TABLES, so the master may serve stale time zone data from cache, while on slave updated data will be loaded from the time zone tables.
2007-03-09 13:12:31 +03:00
--echo #
--echo # Bug#39843 DELETE requires write access to table in subquery in where clause
--echo #
--disable_warnings
DROP TABLE IF EXISTS t1,t2;
--enable_warnings
CREATE TABLE t1 (
table1_rowid SMALLINT NOT NULL
);
CREATE TABLE t2 (
table2_rowid SMALLINT NOT NULL
);
INSERT INTO t1 VALUES (1);
INSERT INTO t2 VALUES (1);
LOCK TABLES t1 WRITE, t2 READ;
--echo # Sub-select should not try to aquire a write lock.
DELETE FROM t1
WHERE EXISTS
(
SELECT 'x'
FROM t2
WHERE t1.table1_rowid = t2.table2_rowid
) ;
--echo # While implementing the patch we didn't break old behavior;
--echo # The following sub-select should still requires a write lock:
--error ER_TABLE_NOT_LOCKED_FOR_WRITE
SELECT * FROM t1 WHERE 1 IN (SELECT * FROM t2 FOR UPDATE);
UNLOCK TABLES;
DROP TABLE t1,t2;
BUG#9953: CONVERT_TZ requires mysql.time_zone_name to be locked The problem was that some facilities (like CONVERT_TZ() function or server HELP statement) may require implicit access to some tables in 'mysql' database. This access was done by ordinary means of adding such tables to the list of tables the query is going to open. However, if we issued LOCK TABLES before that, we would get "table was not locked" error trying to open such implicit tables. The solution is to treat certain tables as MySQL system tables, like we already do for mysql.proc. Such tables may be opened for reading at any moment regardless of any locks in effect. The cost of this is that system table may be locked for writing only together with other system tables, it is disallowed to lock system tables for writing and have any other lock on any other table. After this patch the following tables are treated as MySQL system tables: mysql.help_category mysql.help_keyword mysql.help_relation mysql.help_topic mysql.proc (it already was) mysql.time_zone mysql.time_zone_leap_second mysql.time_zone_name mysql.time_zone_transition mysql.time_zone_transition_type These tables are now opened with open_system_tables_for_read() and closed with close_system_tables(), or one table may be opened with open_system_table_for_update() and closed with close_thread_tables() (the latter is used for mysql.proc table, which is updated as part of normal MySQL server operation). These functions may be used when some tables were opened and locked already. NOTE: online update of time zone tables is not possible during replication, because there's no time zone cache flush neither on LOCK TABLES, nor on FLUSH TABLES, so the master may serve stale time zone data from cache, while on slave updated data will be loaded from the time zone tables.
2007-03-09 13:12:31 +03:00
--echo End of 5.1 tests.
--echo #
--echo # Ensure that FLUSH TABLES doesn't substitute a base locked table
--echo # with a temporary one.
--echo #
--disable_warnings
drop table if exists t1, t2;
--enable_warnings
create table t1 (a int);
create table t2 (a int);
lock table t1 write, t2 write;
create temporary table t1 (a int);
flush table t1;
drop temporary table t1;
select * from t1;
unlock tables;
drop table t1, t2;
--echo #
--echo # Ensure that REPAIR .. USE_FRM works under LOCK TABLES.
--echo #
--disable_warnings
drop table if exists t1, t2;
--enable_warnings
create table t1 (a int);
create table t2 (a int);
lock table t1 write, t2 write;
repair table t1 use_frm;
repair table t1 use_frm;
select * from t1;
select * from t2;
repair table t2 use_frm;
repair table t2 use_frm;
select * from t1;
unlock tables;
drop table t1, t2;
--echo #
--echo # Ensure that mi_copy_status is called for two instances
--echo # of the same table when it is reopened after a flush.
--echo #
--disable_warnings
drop table if exists t1;
drop view if exists v1;
--enable_warnings
create table t1 (c1 int);
create view v1 as select * from t1;
lock tables t1 write, v1 write;
flush table t1;
insert into t1 values (33);
flush table t1;
select * from t1;
unlock tables;
drop table t1;
drop view v1;
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.
2009-12-05 02:02:48 +03:00
--echo #
--echo # WL#4284: Transactional DDL locking
--echo #
--disable_warnings
drop table if exists t1;
--enable_warnings
create table t1 (a int);
connect(con1,localhost,root,,);
set autocommit= 0;
insert into t1 values (1);
lock table t1 write;
--echo # Disconnect
--echo # Ensure that metadata locks will be released if there is an open
--echo # transaction (autocommit=off) in conjunction with lock tables.
disconnect con1;
connection default;
drop table t1;
--echo # Same problem but now for BEGIN
--disable_warnings
drop table if exists t1;
--enable_warnings
create table t1 (a int);
connect(con1,localhost,root,,);
begin;
insert into t1 values (1);
--echo # Disconnect
--echo # Ensure that metadata locks held by the transaction are released.
disconnect con1;
connection default;
drop table t1;
Backport of: ---------------------------------------------------------- revno: 2617.69.2 committer: Konstantin Osipov <kostja@sun.com> branch nick: 5.4-azalea-bugfixing timestamp: Mon 2009-08-03 19:26:04 +0400 message: A fix and a test case for Bug#45035 "Altering table under LOCK TABLES results in "Error 1213 Deadlock found...". If a user had a table locked with LOCK TABLES for READ and for WRITE in the same connection, ALTER TABLE could fail. Root cause analysis: If a connection issues LOCK TABLE t1 write, t1 a read, t1 b read; the new LOCK TABLES code in 6.0 (part of WL 3726) will create the following list of TABLE_LIST objects (thd->locked_tables_list->m_locked_tables): {"t1" "b" tl_read_no_insert}, {"t1" "a" tl_read_no_insert}, {"t1" "t1" tl_write } Later on, when we try to ALTER table t1, mysql_alter_table() closes all TABLE instances and releases its thr_lock locks, keeping only an exclusive metadata lock on t1. But when ALTER is finished, Locked_table_list::reopen_tables() tries to restore the original list of open and locked tables. Before this patch, it used to do so one by one: Open t1 b, get TL_READ_NO_INSERT lock, Open t1 a, get TL_READ_NO_INSERT lock Open t1, try to get TL_WRITE lock, deadlock. The cause of the deadlock is that thr_lock.c doesn't resolve the situation when the read list only consists of locks taken by the same thread, followed by this very thread trying to take a WRITE lock. Indeed, since thr_lock_multi always gets a sorted list of locks, WRITE locks always precede READ locks in the list to lock. Don't try to fix thr_lock.c deficiency, keep this code simple. Instead, try to take all thr_lock locks at once in ::reopen_tables().
2009-12-08 11:38:45 +03:00
--echo #
--echo # Bug#45035 " Altering table under LOCK TABLES results in
--echo # "Error 1213 Deadlock found..."
--echo #
--echo # When reopening tables under LOCK TABLES after ALTER TABLE,
--echo # 6.0 used to be taking thr_lock locks one by one, and
--echo # that would lead to a lock conflict.
--echo # Check that taking all locks at once works.
--echo #
--disable_warnings
drop table if exists t1;
--enable_warnings
create table t1 (i int);
lock tables t1 write, t1 as a read, t1 as b read;
alter table t1 add column j int;
unlock tables;
drop table t1;
create temporary table t1 (i int);
--echo #
--echo # This is just for test coverage purposes,
--echo # when this is allowed, remove the --error.
--echo #
--error ER_CANT_REOPEN_TABLE
lock tables t1 write, t1 as a read, t1 as b read;
alter table t1 add column j int;
unlock tables;
drop table t1;
--echo #
--echo # Separate case for partitioned tables is important
--echo # because each partition has an own thr_lock object.
--echo #
create table t1 (i int) partition by list (i)
(partition p0 values in (1),
partition p1 values in (2,3),
partition p2 values in (4,5));
lock tables t1 write, t1 as a read, t1 as b read;
alter table t1 add column j int;
unlock tables;
drop table t1;
--echo #
--echo # End of 6.0 tests.
--echo #