Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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10.5.0, 10.5.8
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docker mariadb:10.5, centos 7
Description
During regression testing of our application on MariaDB 10.5 we hit a gap lock that doesn't occur in previous versions. Our transactions use isolation level READ COMMITTED so there shouldn't be any gap locks.
Test:
DROP TABLE IF EXISTS `test`;
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CREATE TABLE `test` (
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ID varchar(40) NOT NULL,
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TEST1 varchar(40) DEFAULT NULL,
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TEST2 varchar(15) NOT NULL,
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TEST3 bigint(20) DEFAULT NULL,
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KEY `IDX_TEST` (TEST1, TEST2, TEST3)
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) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC;
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INSERT INTO test (ID, TEST1, TEST2, TEST3) VALUES ('row_a', 'A.123', 'C', 3);
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INSERT INTO test (ID, TEST1, TEST2, TEST3) VALUES ('row_a', 'B.456', 'C', 3);
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SET GLOBAL INNODB_STATUS_OUTPUT_LOCKS = 'ON';
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SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
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BEGIN;
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DELETE FROM test WHERE TEST1 = 'A.123a' and TEST2 = 'C' and TEST3 = 3;
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SHOW ENGINE INNODB STATUS\G
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The delete statement matches 0 rows, but creates a gap lock.
Using a different delete statement doesn't create a gap lock.
DELETE FROM test WHERE TEST1 = 'G.123a' and TEST2 = 'X' and TEST3 = 31;
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Expected Behavior:
no gap lock on the delete statement.
Attachments
Issue Links
- is caused by
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MDEV-19544 Remove innodb_locks_unsafe_for_binlog
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- Closed
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- relates to
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MDEV-16232 Use fewer mini-transactions
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- Stalled
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- Closed
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- Closed
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