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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.
95 lines
1.8 KiB
Text
95 lines
1.8 KiB
Text
# should work with embedded server after mysqltest is fixed
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-- source include/not_embedded.inc
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-- source include/have_innodb.inc
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#
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# BUG#11733: COMMITs should not happen if read-only is set
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#
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--disable_warnings
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DROP TABLE IF EXISTS table_11733 ;
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--enable_warnings
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# READ_ONLY does nothing to SUPER users
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# so we use a non-SUPER one:
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grant CREATE, SELECT, DROP on *.* to test@localhost;
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connect (con1,localhost,test,,test);
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connect (con2,localhost,root,,);
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connection default;
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set global read_only=0;
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# Any transactional engine will do
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create table table_11733 (a int) engine=InnoDb;
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connection con1;
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BEGIN;
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insert into table_11733 values(11733);
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connection default;
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send set global read_only=1;
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connection con2;
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let $wait_condition=
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select count(*) = 1 from information_schema.processlist
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where state = "Flushing tables" and info = "set global read_only=1";
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--source include/wait_condition.inc
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connection con1;
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select @@global.read_only;
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--error ER_LOCK_DEADLOCK
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select * from table_11733 ;
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COMMIT;
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connection default;
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reap;
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set global read_only=0;
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drop table table_11733 ;
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drop user test@localhost;
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disconnect con1;
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#
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# Bug #35732: read-only blocks SELECT statements in InnoDB
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#
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# Test 1: read only mode
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GRANT CREATE, SELECT, DROP ON *.* TO test@localhost;
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connect(con1, localhost, test, , test);
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connection default;
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CREATE TABLE t1(a INT) ENGINE=INNODB;
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INSERT INTO t1 VALUES (0), (1);
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SET GLOBAL read_only=1;
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connection con1;
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SELECT * FROM t1;
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BEGIN;
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SELECT * FROM t1;
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COMMIT;
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connection default;
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SET GLOBAL read_only=0;
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#
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# Test 2: global read lock
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#
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FLUSH TABLES WITH READ LOCK;
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connection con1;
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SELECT * FROM t1;
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BEGIN;
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SELECT * FROM t1;
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COMMIT;
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connection default;
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UNLOCK TABLES;
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DROP TABLE t1;
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DROP USER test@localhost;
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disconnect con1;
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disconnect con2;
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--echo echo End of 5.1 tests
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