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--source include/have_innodb.inc
--source include/have_debug_sync.inc
--source include/count_sessions.inc
# Purge can cause deadlock in the test, requesting page's RW_X_LATCH for trx
# ids reseting, after trx 2 acqured RW_S_LATCH and suspended in debug sync point
# lock_trx_handle_wait_enter, waiting for upd_cont signal, which must be
# emitted after the last SELECT in this test. The last SELECT will hang waiting
# for purge RW_X_LATCH releasing, and trx 2 will be rolled back by timeout.
# There is deadlock_report_before_lock_releasing sync point in
# Deadlock::report(), which is waiting for sel_cont signal under
# lock_sys_t lock. The signal must be issued after "UPDATE t SET b = 100"
# rollback, and that rollback is executing undo record, which is blocked on
# dict_sys latch request. dict_sys is locked by the thread of statistics
# update(dict_stats_save()), and during that update lock_sys lock is requested,
# and can't be acquired as Deadlock::report() holds it. We have to disable
# statistics update to make the test stable.
CREATE TABLE t (a int PRIMARY KEY, b int) engine = InnoDB STATS_PERSISTENT=0;
CREATE TABLE t2 (a int PRIMARY KEY) engine = InnoDB STATS_PERSISTENT=0;
INSERT INTO t VALUES (10, 10), (20, 20), (30, 30);
INSERT INTO t2 VALUES (10), (20), (30);
BEGIN; # trx 1
# The following update is necessary to increase the transaction weight, which is
# calculated as the number of locks + the number of undo records during deadlock
# report. Victim's transaction should have minimum weight. We need trx 2 to be
# choosen as victim, that's why we need to increase the current transaction
# weight.
UPDATE t2 SET a = a + 100;
SELECT * FROM t WHERE a = 20 FOR UPDATE;
--connect(con_2,localhost,root,,)
# RC is necessary to do semi-consistent read
SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
# It will be hit on trying to lock (20,20).
SET DEBUG_SYNC = 'lock_trx_handle_wait_enter SIGNAL upd_locked WAIT_FOR upd_cont';
SET DEBUG_SYNC = 'trx_t_release_locks_enter SIGNAL sel_cont WAIT_FOR upd_cont_2';
BEGIN; # trx 2
# We must not modify primary key fields to cause rr_sequential() read record
# function choosing in mysql_update(), i.e. both query_plan.using_filesort and
# query_plan.using_io_buffer must be false during init_read_record() call.
# The following UPDATE will be chosen as deadlock victim and rolled back.
--send UPDATE t SET b = 100
--connection default
SET DEBUG_SYNC="now WAIT_FOR upd_locked";
SET DEBUG_SYNC="deadlock_report_before_lock_releasing SIGNAL upd_cont WAIT_FOR sel_cont";
SET DEBUG_SYNC="lock_wait_before_suspend SIGNAL sel_before_suspend";
# If the bug is not fixed, the following SELECT will crash, as the above UPDATE
# will reset trx->lock.wait_thr during rollback
--send SELECT * FROM t WHERE a = 10 FOR UPDATE;
--connect(con_3,localhost,root,,)
SET DEBUG_SYNC="now WAIT_FOR sel_before_suspend";
SET DEBUG_SYNC="now SIGNAL upd_cont_2";
--disconnect con_3
--connection con_2
--error ER_LOCK_DEADLOCK
--reap
--disconnect con_2
--connection default
--reap
SET DEBUG_SYNC = 'RESET';
DROP TABLE t;
DROP TABLE t2;
--source include/wait_until_count_sessions.inc
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