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;
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
set autocommit=0;
set @@innodb_table_locks=0;
lock table t1 write;
update t1 set x=10 where id = 2;
SELECT * from t1 where id = 2;
id	x
2	2
UPDATE t1 set x=3 where id = 2;
commit;
SELECT * from t1;
id	x
0	0
1	1
2	3
commit;
unlock tables;
commit;
select * from t1;
id	x
0	0
1	1
2	10
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;