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235f33e360
It's possible that MDL conflict handling code is called more than once for a transaction when: - it holds more than one conflicting MDL lock - reschedule_waiters() is executed, which results in repeated attempts to BF-abort already aborted transaction. In such situations, it might be that BF-aborting logic sees a partially rolled back transaction and erroneously decides on future actions for such a transaction. The specific situation tested and fixed is when a SR transaction applied in the node gets BF-aborted by a started TOI operation. It's then caught with the server transaction already rolled back, but with no MDL locks yet released. This caused wrong state detection for such a transaction during repeated MDL conflict handling code execution. Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
34 lines
1.1 KiB
Text
34 lines
1.1 KiB
Text
connection node_2;
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connection node_1;
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connect node_1a,127.0.0.1,root,,test,$NODE_MYPORT_1;
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connection node_1;
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CREATE TABLE t1 (f1 INTEGER PRIMARY KEY) ENGINE=InnoDB;
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SET GLOBAL DEBUG_DBUG = 'd,sync.wsrep_rollback_mdl_release';
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connection node_2;
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SET SESSION wsrep_trx_fragment_size = 1;
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START TRANSACTION;
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INSERT INTO t1 VALUES (1);
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connection node_1a;
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SELECT COUNT(*) FROM t1;
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COUNT(*)
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0
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SET SESSION wsrep_retry_autocommit = 0;
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SET DEBUG_SYNC = 'ha_write_row_start SIGNAL may_toi WAIT_FOR bf_abort';
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INSERT INTO t1 VALUES (2);
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connection node_1;
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SET DEBUG_SYNC = 'now WAIT_FOR may_toi';
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SET DEBUG_SYNC = 'after_wsrep_thd_abort WAIT_FOR sync.wsrep_rollback_mdl_release_reached';
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TRUNCATE TABLE t1;
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connection node_1a;
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ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
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SET DEBUG_SYNC = 'now SIGNAL signal.wsrep_rollback_mdl_release';
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connection node_2;
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INSERT INTO t1 VALUES (3);
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ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
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connection node_1;
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SET GLOBAL DEBUG_DBUG = '';
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SET DEBUG_SYNC = 'RESET';
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DROP TABLE t1;
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disconnect node_1a;
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disconnect node_2;
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disconnect node_1;
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