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33d41167c5
When MDEV-19544 (commit 1a6f470464)
simplified the initialization of the local variable
set_also_gap_locks, an inadvertent change was included.
Essentially, all code branches that are executed when
set_also_gap_locks hold must also ensure that
trx->isolation_level > TRX_ISO_READ_COMMITTED holds.
This was being violated in a few code paths.
It turns out that there is an even simpler fix: Remove the test
of thd_is_select() completely. In that way, the first part of
UPDATE or DELETE should work exactly like SELECT...FOR UPDATE.
thd_is_select(): Remove.
35 lines
1 KiB
Text
35 lines
1 KiB
Text
CREATE TABLE t1(a INT PRIMARY KEY, b VARCHAR(40), c INT, INDEX(b,c))
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ENGINE=InnoDB;
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INSERT INTO t1 VALUES (1,'1',1),(2,'2',1);
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SET @save_locks= @@GLOBAL.innodb_status_output_locks;
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SET GLOBAL INNODB_STATUS_OUTPUT_LOCKS = 'ON';
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SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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BEGIN;
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DELETE FROM t1 WHERE b='2' AND c=2;
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SHOW ENGINE INNODB STATUS;
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Type Name Status
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InnoDB 2 lock struct(s), 1 row lock(s)
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ROLLBACK;
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SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
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BEGIN;
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DELETE FROM t1 WHERE b='2' AND c=2;
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SHOW ENGINE INNODB STATUS;
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Type Name Status
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InnoDB 2 lock struct(s), 1 row lock(s)
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ROLLBACK;
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SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
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BEGIN;
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DELETE FROM t1 WHERE b='2' AND c=2;
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SHOW ENGINE INNODB STATUS;
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Type Name Status
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InnoDB 1 lock struct(s), 0 row lock(s)
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ROLLBACK;
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SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
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BEGIN;
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DELETE FROM t1 WHERE b='2' AND c=2;
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SHOW ENGINE INNODB STATUS;
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Type Name Status
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InnoDB 1 lock struct(s), 0 row lock(s)
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ROLLBACK;
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SET GLOBAL INNODB_STATUS_OUTPUT_LOCKS = @save_locks;
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DROP TABLE t1;
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