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set global innodb_table_locks=1;
select @@innodb_table_locks;
@@innodb_table_locks
1
drop table if exists t1;
set @@innodb_table_locks=1;
create table t1 (id integer, x integer) engine=INNODB;
insert into t1 values(0, 0);
set autocommit=0;
SELECT * from t1 where id = 0 FOR UPDATE;
id x
0 0
set autocommit=0;
lock table t1 write;
update t1 set x=1 where id = 0;
select * from t1;
id x
0 1
commit;
update t1 set x=2 where id = 0;
commit;
unlock tables;
select * from t1;
id x
0 2
commit;
drop table t1;
#
# Old lock method (where LOCK TABLE was ignored by InnoDB) no longer
# works when LOCK TABLE ... WRITE is used due to fix for bugs #46272
# "MySQL 5.4.4, new MDL: unnecessary and bug #37346 "innodb does not
# detect deadlock between update and alter table". But it still works
# for LOCK TABLE ... READ.
#
set @@innodb_table_locks=0;
create table t1 (id integer primary key, x integer) engine=INNODB;
insert into t1 values(0, 0),(1,1),(2,2);
commit;
SELECT * from t1 where id = 0 FOR UPDATE;
id x
0 0
# Connection 'con2'.
set autocommit=0;
set @@innodb_table_locks=0;
# The following statement should block because SQL-level lock
# is taken on t1 which will wait until concurrent transaction
# is commited.
# Sending:
lock table t1 write;;
# Connection 'con1'.
# Wait until LOCK TABLE is blocked on SQL-level lock.
# We should be able to do UPDATEs and SELECTs within transaction.
update t1 set x=1 where id = 0;
select * from t1;
id x
0 1
1 1
2 2
# Unblock LOCK TABLE.
commit;
# Connection 'con2'.
# Reap LOCK TABLE.
unlock tables;
# Connection 'con1'.
select * from t1 where id = 0 for update;
id x
0 1
# Connection 'con2'.
# The below statement should not be blocked as LOCK TABLES ... READ
# does not take strong SQL-level lock on t1. SELECTs which do not
# conflict with transaction in the first connections should not be
# blocked.
lock table t1 read;
select * from t1;
id x
0 1
1 1
2 2
select * from t1 where id = 1 lock in share mode;
id x
1 1
unlock tables;
select * from t1;
id x
0 1
1 1
2 2
commit;
# Connection 'con1'.
commit;
drop table t1;
#
#Bug#12842206 INNODB LOCKING REGRESSION FOR INSERT IGNORE
#fixed by re-fixing Bug#7975
#aka Bug#11759688 52020: InnoDB can still deadlock on just INSERT...
#
CREATE TABLE t1 (a INT PRIMARY KEY, b INT NOT NULL) ENGINE=InnoDB;
INSERT INTO t1 VALUES(3,1);
BEGIN;
INSERT IGNORE INTO t1 VALUES(3,14);
BEGIN;
INSERT IGNORE INTO t1 VALUES(3,23);
SELECT * FROM t1 FOR UPDATE;
COMMIT;
a b
3 1
COMMIT;
DROP TABLE t1;
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