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# Bug #28176910
# PERFORMANCE_SCHEMA.DATA_LOCKS.OBJECT_INSTANCE_BEGIN
# CHANGES DEPENDING ON ORDER
CREATE TABLE t1(
id INT PRIMARY KEY
) Engine=InnoDB;
INSERT INTO t1 VALUES (1);
BEGIN;
SELECT * FROM t1 WHERE id=1 FOR SHARE;
id
1
SELECT * FROM t1 WHERE id=1 FOR UPDATE;
id
1
SELECT COUNT(DISTINCT engine_lock_id) FROM performance_schema.data_locks;
COUNT(DISTINCT engine_lock_id)
4
SELECT
lock_type,
lock_mode,
lock_status,
lock_data
FROM performance_schema.data_locks
ORDER BY 1,2,3,4;
lock_type lock_mode lock_status lock_data
RECORD S,REC_NOT_GAP GRANTED 1
RECORD X,REC_NOT_GAP GRANTED 1
TABLE IS GRANTED NULL
TABLE IX GRANTED NULL
BEGIN;
SET DEBUG_SYNC = 'lock_wait_will_wait SIGNAL C1_will_wait';
SELECT * FROM t1 FOR UPDATE;;
SET DEBUG_SYNC = 'now WAIT_FOR C1_will_wait';
SELECT
r.object_name,r.lock_type,r.lock_mode,r.lock_status,r.lock_data ,
b.object_name,b.lock_type,b.lock_mode,b.lock_status,b.lock_data
FROM performance_schema.data_lock_waits
JOIN performance_schema.data_locks r
ON(r.engine_lock_id = requesting_engine_lock_id)
JOIN performance_schema.data_locks b
ON(b.engine_lock_id = blocking_engine_lock_id)
ORDER BY b.lock_mode;
object_name lock_type lock_mode lock_status lock_data object_name lock_type lock_mode lock_status lock_data
t1 RECORD X WAITING 1 t1 RECORD S,REC_NOT_GAP GRANTED 1
t1 RECORD X WAITING 1 t1 RECORD X,REC_NOT_GAP GRANTED 1
SELECT r.object_name,r.lock_type,r.lock_mode,r.lock_status,r.lock_data
FROM information_schema.innodb_trx
JOIN performance_schema.data_locks r
ON(r.engine_lock_id = trx_requested_lock_id);
object_name lock_type lock_mode lock_status lock_data
t1 RECORD X WAITING 1
ROLLBACK;
id
1
ROLLBACK;
DROP TABLE t1;
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