1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
|
stop slave;
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
reset master;
reset slave;
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
start slave;
DROP DATABASE IF EXISTS mysqltest;
DROP TABLE IF EXISTS t1, t2, t3, t4, v1;
DROP VIEW IF EXISTS t1, t2, t3, t4, v1;
DROP PROCEDURE IF EXISTS lock_t1_excl;
DROP PROCEDURE IF EXISTS count_t2;
DROP PROCEDURE IF EXISTS update_t2;
DROP TRIGGER IF EXISTS t1_ai;
#
# WL3561 - transactional LOCK TABLE - Syntax tests
# ================================================
CREATE TABLE t1 (c1 INT ) ENGINE=InnoDB;
CREATE TABLE t2 (c2 INT ) ENGINE=InnoDB;
CREATE TABLE t3 (c3 INT ) ENGINE=InnoDB;
#
# Valid syntax for non-transactional locks.
LOCK TABLE t1 READ, t2 WRITE;
UNLOCK TABLES;
LOCK TABLE t1 READ LOCAL, t2 LOW_PRIORITY WRITE;
UNLOCK TABLES;
#
# Valid syntax for transactional locks.
LOCK TABLE t1 IN SHARE MODE, t2 IN EXCLUSIVE MODE;
UNLOCK TABLES;
#
# Valid syntax for transactional locks with NOWAIT option.
## In the preliminary reference implementation we expect these errors:
## NOWAIT+SHARE="timed out", NOWAIT+EXCLUSIVE="not supported".
## Statements abort on first error.
LOCK TABLE t1 IN SHARE MODE NOWAIT, t2 IN EXCLUSIVE MODE NOWAIT;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
LOCK TABLE t1 IN EXCLUSIVE MODE NOWAIT, t2 IN SHARE MODE NOWAIT;
ERROR 42000: Table 't1' uses an extension that doesn't exist in this MySQL version
LOCK TABLE t1 IN EXCLUSIVE MODE, t2 IN SHARE MODE NOWAIT;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
#
# Valid syntax for aliases with and without 'AS'.
LOCK TABLE t1 AS a1 READ, t2 a2 WRITE;
UNLOCK TABLES;
LOCK TABLE t1 AS a1 IN SHARE MODE, t2 a2 IN EXCLUSIVE MODE;
UNLOCK TABLES;
#
# Transactional locks taken on a view.
CREATE VIEW v1 AS SELECT * FROM t1, t2 WHERE t1.c1 = t2.c2;
LOCK TABLE v1 IN SHARE MODE;
LOCK TABLE v1 IN EXCLUSIVE MODE;
DROP VIEW v1;
#
# Locking INFORMATION_SCHEMA fails on missing privileges.
LOCK TABLE information_schema.tables IN SHARE MODE;
ERROR 42000: Access denied for user 'root'@'localhost' to database 'information_schema'
LOCK TABLE information_schema.tables IN EXCLUSIVE MODE;
ERROR 42000: Access denied for user 'root'@'localhost' to database 'information_schema'
LOCK TABLE information_schema.tables READ;
ERROR 42000: Access denied for user 'root'@'localhost' to database 'information_schema'
LOCK TABLE information_schema.tables WRITE;
ERROR 42000: Access denied for user 'root'@'localhost' to database 'information_schema'
#
# The new keywords EXCLUSIVE and NOWAIT are not reserved words.
CREATE TABLE t4 (exclusive INT, nowait INT) ENGINE=InnoDB;
LOCK TABLE t4 WRITE;
DROP TABLE t4;
#
# Syntax errors for misspelled modes or left out symbols.
##-------------------------------------------------------
LOCK TABLE t1 IN SHARED MODE;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SHARED MODE' at line 1
LOCK TABLE t1 SHARE MODE;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'MODE' at line 1
LOCK TABLE t1 IN SHARE;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
LOCK TABLE t1 IN MODE;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'MODE' at line 1
LOCK TABLE t1 READ NOWAIT, t2 WRITE NOWAIT;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'NOWAIT, t2 WRITE NOWAIT' at line 1
LOCK TABLE t1 READ NOWAIT, t2 IN EXCLUSIVE MODE NOWAIT;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'NOWAIT, t2 IN EXCLUSIVE MODE NOWAIT' at line 1
LOCK TABLE t1 IN SHARE MODE NOWAIT, t2 WRITE NOWAIT;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'NOWAIT' at line 1
LOCK TABLE t1 IN SHARED MODE NOWAIT;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SHARED MODE NOWAIT' at line 1
LOCK TABLE t1 SHARE MODE NOWAIT;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'MODE NOWAIT' at line 1
LOCK TABLE t1 IN SHARE NOWAIT;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'NOWAIT' at line 1
LOCK TABLE t1 IN MODE NOWAIT;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'MODE NOWAIT' at line 1
##----------------------
## End of syntax errors.
#
#
# WL3561 - transactional LOCK TABLE - Lock method conversion
# ==========================================================
#
# Implicit lock method conversion due to mix in statement.
LOCK TABLE t1 READ, t2 IN EXCLUSIVE MODE;
Warnings:
Warning 1613 Converted to non-transactional lock on 't2'
UNLOCK TABLES;
# Lock t1 share (converted to read), t2 write.
LOCK TABLE t1 IN SHARE MODE, t2 WRITE;
Warnings:
Warning 1613 Converted to non-transactional lock on 't1'
# Show t1 is read locked, t2 write locked.
INSERT INTO t1 SELECT * FROM t2;
ERROR HY000: Table 't1' was locked with a READ lock and can't be updated
INSERT INTO t2 SELECT * FROM t1;
#
# Implicit lock method conversion due to existing non-transact. locks.
# Implicitly unlock existing non-transactional locks and take new ones.
# Lock t1 exclusive (converted to write), t2 share (converted to read).
LOCK TABLE t1 IN EXCLUSIVE MODE, t2 IN SHARE MODE;
Warnings:
Warning 1613 Converted to non-transactional lock on 't1'
Warning 1613 Converted to non-transactional lock on 't2'
# Show t1 is write locked, t2 read locked.
INSERT INTO t1 SELECT * FROM t2;
INSERT INTO t2 SELECT * FROM t1;
ERROR HY000: Table 't2' was locked with a READ lock and can't be updated
UNLOCK TABLES;
#
# Reject lock method conversion in strict mode.
# Set strict mode.
SET @wl3561_save_sql_mode= @@SQL_MODE;
SET @@SQL_MODE= 'STRICT_ALL_TABLES';
# Try mixed mode locks.
LOCK TABLE t1 READ, t2 IN EXCLUSIVE MODE;
ERROR HY000: Cannot convert to non-transactional lock in strict mode on 't2'
LOCK TABLE t1 IN SHARE MODE, t2 WRITE;
ERROR HY000: Cannot convert to non-transactional lock in strict mode on 't1'
# Lock non-transactional.
LOCK TABLE t1 READ, t2 WRITE;
# Try transactional locks on top of the existing non-transactional locks.
LOCK TABLE t1 IN SHARE MODE, t2 IN EXCLUSIVE MODE;
ERROR HY000: Cannot convert to non-transactional lock in strict mode on 't1'
## Error is reported on first table only. Show both errors:
SHOW WARNINGS;
Level Code Message
Error 1614 Cannot convert to non-transactional lock in strict mode on 't1'
Error 1614 Cannot convert to non-transactional lock in strict mode on 't2'
UNLOCK TABLES;
SET @@SQL_MODE= @wl3561_save_sql_mode;
#
# Reject lock method conversion in an active transaction.
# Start transaction.
START TRANSACTION;
# Try mixed mode locks.
LOCK TABLE t1 READ, t2 IN EXCLUSIVE MODE;
ERROR HY000: Cannot convert to non-transactional lock in an active transaction on 't2'
LOCK TABLE t1 IN SHARE MODE, t2 WRITE;
ERROR HY000: Cannot convert to non-transactional lock in an active transaction on 't1'
COMMIT;
#
# Implicit lock method conversion for non-transactional storage engine.
# Create a non-transactional table.
CREATE TABLE t4 (c4 INT) ENGINE= MyISAM;
# Request a transactional lock, which is converted to non-transactional.
LOCK TABLE t4 IN SHARE MODE;
Warnings:
Warning 1613 Converted to non-transactional lock on 't4'
# Try a conflict with the existing non-transactional lock.
INSERT INTO t4 VALUES(444);
ERROR HY000: Table 't4' was locked with a READ lock and can't be updated
UNLOCK TABLES;
# Set strict mode.
SET @@SQL_MODE= 'STRICT_ALL_TABLES';
# Try a transactional lock, which would need a conversion.
LOCK TABLE t4 IN SHARE MODE;
ERROR HY000: Cannot convert to non-transactional lock in strict mode on 't4'
SET @@SQL_MODE= @wl3561_save_sql_mode;
#
# View with transactional and non-transactional storage engine.
CREATE VIEW v1 AS SELECT * FROM t3, t4 WHERE t3.c3 = t4.c4;
# Request a share lock on the view, which is converted to read locks.
LOCK TABLE v1 IN SHARE MODE;
Warnings:
Warning 1613 Converted to non-transactional lock on 't3'
Warning 1613 Converted to non-transactional lock on 't4'
# Show that read locks on the base tables prohibit writing ...
INSERT INTO t3 SELECT * FROM t4;
ERROR HY000: Table 't3' was locked with a READ lock and can't be updated
INSERT INTO t4 SELECT * FROM t3;
ERROR HY000: Table 't4' was locked with a READ lock and can't be updated
# ... but allow reading.
SELECT COUNT(*) FROM t3, t4 WHERE t3.c3 = t4.c4;
COUNT(*)
0
SELECT COUNT(*) FROM v1;
COUNT(*)
0
## Report conversion on view due to existing non-transactional locks.
LOCK TABLE v1 IN EXCLUSIVE MODE;
Warnings:
Warning 1613 Converted to non-transactional lock on 'v1'
INSERT INTO t3 VALUES(333);
INSERT INTO t4 VALUES(444);
INSERT INTO t1 VALUES(111);
ERROR HY000: Table 't1' was not locked with LOCK TABLES
UNLOCK TABLES;
## Now report conversion on base table again.
LOCK TABLE v1 IN EXCLUSIVE MODE;
Warnings:
Warning 1613 Converted to non-transactional lock on 't3'
Warning 1613 Converted to non-transactional lock on 't4'
INSERT INTO t3 VALUES(333);
INSERT INTO t4 VALUES(444);
INSERT INTO t1 VALUES(111);
ERROR HY000: Table 't1' was not locked with LOCK TABLES
UNLOCK TABLES;
DROP VIEW v1;
TRUNCATE t4;
#
# Insufficient privileges do not unlock tables nor end transactions.
# Prepare database, tables and an user with insufficient privileges.
# Make a new connection with this user.
CREATE DATABASE mysqltest;
CREATE TABLE mysqltest.t5 (c5 INT) ENGINE=InnoDB;
CREATE TABLE mysqltest.t6 (c6 INT) ENGINE=InnoDB;
CREATE USER mysqltest_1@localhost;
GRANT SELECT, INSERT ON mysqltest.* TO mysqltest_1@localhost;
# connection conn1.
# Show sufficient privileges to lock tables in the test database.
LOCK TABLE t1 READ, t2 WRITE;
# Show insufficient privileges in the mysqltest database.
LOCK TABLE mysqltest.t5 READ, mysqltest.t6 WRITE;
ERROR 42000: Access denied for user 'mysqltest_1'@'localhost' to database 'mysqltest'
# Show that the locks in 'test' still exist.
INSERT INTO t1 SELECT * FROM t2;
ERROR HY000: Table 't1' was locked with a READ lock and can't be updated
INSERT INTO t2 SELECT * FROM t1;
# Unlock tables.
UNLOCK TABLES;
# Start transaction.
START TRANSACTION;
# Insert a value.
INSERT INTO t1 VALUES(111);
# Try a lock that fails on privileges.
LOCK TABLE mysqltest.t5 READ;
ERROR 42000: Access denied for user 'mysqltest_1'@'localhost' to database 'mysqltest'
# Rollback transaction.
ROLLBACK;
# Show that the inserted value has gone.
SELECT * FROM t1;
c1
# Drop the connection with the unprivileged user.
# connection default.
#
# Sufficient privileges do unlock tables and end transactions.
# Grant sufficient privileges to the user.
# Make a new connection with this user.
GRANT SELECT, INSERT, LOCK TABLES ON mysqltest.* TO mysqltest_1@localhost;
# connection conn1.
# Lock tables in the test database.
LOCK TABLE t1 READ, t2 WRITE;
# Lock tables in the mysqltest database.
LOCK TABLE mysqltest.t5 READ, mysqltest.t6 WRITE;
# Show that the locks in 'test' have been replaced ...
INSERT INTO t1 SELECT * FROM t2;
ERROR HY000: Table 't1' was not locked with LOCK TABLES
INSERT INTO t2 SELECT * FROM t1;
ERROR HY000: Table 't2' was not locked with LOCK TABLES
# ... by the locks in 'mysqltest'.
INSERT INTO mysqltest.t5 SELECT * FROM mysqltest.t6;
ERROR HY000: Table 't5' was locked with a READ lock and can't be updated
INSERT INTO mysqltest.t6 SELECT * FROM mysqltest.t5;
# Unlock tables.
UNLOCK TABLES;
# Start transaction.
START TRANSACTION;
# Insert a value.
INSERT INTO t1 VALUES(111);
# Take a new lock.
LOCK TABLE mysqltest.t5 READ;
# Rollback transaction.
ROLLBACK;
UNLOCK TABLES;
# Show that the inserted value had been committed.
SELECT * FROM t1;
c1
111
TRUNCATE t1;
# connection default.
UNLOCK TABLES;
DROP USER mysqltest_1@localhost;
DROP DATABASE mysqltest;
DROP TABLE t1, t2, t3, t4;
#
# WL3594 - transactional LOCK TABLE Testing - Functional tests
# ============================================================
# Prepare tables and connections.
# Set AUTOCOMMIT= 0 in each connection.
SET AUTOCOMMIT= 0;
CREATE TABLE t1 (c1 INT) ENGINE=InnoDB;
CREATE TABLE t2 (c2 INT) ENGINE=InnoDB;
# connection conn1.
SET AUTOCOMMIT= 0;
# connection conn2.
SET AUTOCOMMIT= 0;
# connection default.
#
# Transactional lock behaviour:
# LOCK TABLE does _not_ commit a transaction.
# Insert a value.
INSERT INTO t1 VALUES (111);
# Lock transactional.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# Rollback.
ROLLBACK;
# Show that the inserted value has gone.
SELECT * FROM t1;
c1
#
# After LOCK TABLE one can access tables not mentioned in LOCK TABLE.
# Lock t1 transactional.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# Insert a value into t2.
INSERT INTO t2 VALUES (222);
# Show that the inserted value is indeed in the table.
SELECT * FROM t2;
c2
222
#
# One can issue LOCK TABLE many times, adding more tables.
# Lock t2 transactional.
LOCK TABLE t2 IN EXCLUSIVE MODE;
#
# LOCK TABLE does not rollback a transaction.
# Show that the inserted value is still in the table.
SELECT * FROM t2;
c2
222
# Rollback transaction.
ROLLBACK;
# Show that the inserted value has gone.
SELECT * FROM t2;
c2
#
# Tables are unlocked at the end of transaction (commit).
# Take an exclusive lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# Commit.
COMMIT;
# connection conn1.
# Take an exclusive lock.
# This would fail after timeout if t1 is still locked.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# Commit.
COMMIT;
# connection default.
#
# Tables are unlocked at the end of transaction (rollback).
# Take an exclusive lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# Rollback.
ROLLBACK;
# connection conn1.
# Take an exclusive lock.
# This would fail after timeout if t1 is still locked.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# Rollback.
ROLLBACK;
# connection default.
#
# UNLOCK TABLES does not touch a transaction when
# no non-transactional table locks exist.
# Take a transactional lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# Insert a value.
INSERT INTO t1 VALUES(111);
# Unlock (non-transactional) table locks.
UNLOCK TABLES;
# Show that the inserted value is still in the table.
SELECT * FROM t1;
c1
111
# Rollback.
ROLLBACK;
# Show that the inserted value has gone.
SELECT * FROM t1;
c1
#
# UNLOCK TABLES commits a transaction when
# non-transactional table locks exist.
# Take a non-transactional lock.
LOCK TABLE t1 WRITE;
# Insert a value.
INSERT INTO t1 VALUES(111);
# Unlock (non-transactional) table locks.
UNLOCK TABLES;
# Show that the inserted value is still in the table.
SELECT * FROM t1;
c1
111
# Rollback.
ROLLBACK;
# Show that the inserted value is still in the table.
SELECT * FROM t1;
c1
111
TRUNCATE t1;
#
# START TRANSACTION removes a previous lock.
# Take an exclusive lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# Start transaction.
START TRANSACTION;
# connection conn1.
# Take an exclusive lock.
# This would fail after timeout if t1 is still locked.
LOCK TABLE t1 IN EXCLUSIVE MODE;
COMMIT;
# connection default.
COMMIT;
#
# With Auto commit on, transactional locks will be ignored
# Set AUTOCOMMIT= 1.
SET AUTOCOMMIT= 1;
# Take an exclusive lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# connection conn1.
# Set AUTOCOMMIT= 1.
SET AUTOCOMMIT= 1;
# Take an exclusive lock.
# This would fail after timeout if t1 is still locked.
LOCK TABLE t1 IN SHARE MODE;
SET AUTOCOMMIT= 0;
COMMIT;
# connection default.
UNLOCK TABLES;
SET AUTOCOMMIT= 0;
COMMIT;
#
# With Auto commit on, transactional locks can time out.
# Default connection runs in transactional mode.
# Set AUTOCOMMIT= 0.
SET AUTOCOMMIT= 0;
# Take an exclusive lock, which persists.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# connection conn1.
# conn1 runs in autocommit mode.
# Set AUTOCOMMIT= 1.
SET AUTOCOMMIT= 1;
# Try an exclusive lock,
# which times out though running in autocommit mode.
LOCK TABLE t1 IN SHARE MODE;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
SET AUTOCOMMIT= 0;
COMMIT;
# connection default.
UNLOCK TABLES;
SET AUTOCOMMIT= 0;
COMMIT;
#
# Normal WRITE locks go before readers (autocommit).
# Set AUTOCOMMIT= 1.
SET AUTOCOMMIT= 1;
# Insert a value.
INSERT INTO t1 VALUES(111);
# Take a non-transactional lock.
LOCK TABLE t1 READ;
# connection conn1.
# Set AUTOCOMMIT= 1.
SET AUTOCOMMIT= 1;
# Take a non-transactional WRITE lock,
# which waits in background until first read lock is released.
LOCK TABLE t1 WRITE;
# connection default.
# Wait for the helper thread to sit on its lock.
# connection conn2.
# Set AUTOCOMMIT= 1.
SET AUTOCOMMIT= 1;
# Take a non-transactional READ lock,
# which waits in background until the WRITE lock is released.
LOCK TABLE t1 READ;
# connection default.
# Wait for the helper threads to sit on their locks.
# Unlock this connections non-transactional lock.
UNLOCK TABLES;
# connection conn1.
# Now the WRITE lock is taken.
# Insert a value.
INSERT INTO t1 VALUES(1111);
# Unlock table.
UNLOCK TABLES;
# connection conn2.
# Now the READ lock is taken.
# Select from the table.
SELECT * FROM t1;
c1
111
1111
# Unlock table.
UNLOCK TABLES;
# connection default.
TRUNCATE t1;
#
# LOW_PRIORITY WRITE locks wait for readers (autocommit).
# Insert a value.
INSERT INTO t1 VALUES(111);
# Take a non-transactional lock.
LOCK TABLE t1 READ;
# connection conn1.
# Take a non-transactional LOW_PRIORITY WRITE lock,
# which waits in background until all read locks are released.
LOCK TABLE t1 LOW_PRIORITY WRITE;
# connection default.
# Wait for the helper thread to sit on its lock.
# connection conn2.
# Take a non-transactional READ lock,
# which goes before the LOW_PRIORITY WRITE lock.
LOCK TABLE t1 READ;
# The READ lock could be taken immediately.
# Select from the table.
SELECT * FROM t1;
c1
111
# Unlock table.
UNLOCK TABLES;
SET AUTOCOMMIT= 0;
# connection default.
# Unlock this connections non-transactional lock.
UNLOCK TABLES;
# connection conn1.
# Now the LOW_PRIORITY WRITE lock is taken.
# Insert a value.
INSERT INTO t1 VALUES(1111);
# Unlock table.
UNLOCK TABLES;
SET AUTOCOMMIT= 0;
# connection default.
TRUNCATE t1;
SET AUTOCOMMIT= 0;
COMMIT;
#
# Normal WRITE locks go before readers (transaction).
# Insert a value.
INSERT INTO t1 VALUES(111);
COMMIT;
# Take a non-transactional lock.
LOCK TABLE t1 READ;
# connection conn1.
# Take a non-transactional WRITE lock,
# which waits in background until first read lock is released.
LOCK TABLE t1 WRITE;
# connection default.
# Wait for the helper thread to sit on its lock.
# connection conn2.
# Take a non-transactional READ lock,
# which waits in background until the WRITE lock is released.
LOCK TABLE t1 READ;
# connection default.
# Wait for the helper threads to sit on their locks.
# Unlock this connections non-transactional lock.
UNLOCK TABLES;
# connection conn1.
# Now the WRITE lock is taken.
# Insert a value.
INSERT INTO t1 VALUES(1111);
# Unlock table.
UNLOCK TABLES;
# connection conn2.
# Now the READ lock is taken.
# Select from the table.
SELECT * FROM t1;
c1
111
1111
# Unlock table.
UNLOCK TABLES;
# connection default.
TRUNCATE t1;
COMMIT;
#
# LOW_PRIORITY WRITE behaves like WRITE in transaction mode.
# Insert a value.
INSERT INTO t1 VALUES(111);
COMMIT;
# Take a non-transactional lock.
LOCK TABLE t1 READ;
# connection conn1.
# Take a non-transactional LOW_PRIORITY WRITE lock,
# which waits in background until first read lock is released.
LOCK TABLE t1 LOW_PRIORITY WRITE;
# connection default.
# Wait for the helper thread to sit on its lock.
# connection conn2.
# Take a non-transactional READ lock,
# which waits in background for the LOW_PRIORITY WRITE lock.
LOCK TABLE t1 READ;
# connection default.
# Wait for the helper threads to sit on their locks.
# Unlock this connections non-transactional lock.
UNLOCK TABLES;
# connection conn1.
# Now the LOW_PRIORITY WRITE lock is taken.
# Insert a value.
INSERT INTO t1 VALUES(1111);
# Unlock table.
UNLOCK TABLES;
# connection conn2.
# Now the READ lock is taken.
# Select from the table.
SELECT * FROM t1;
c1
111
1111
# Unlock table.
UNLOCK TABLES;
# connection default.
TRUNCATE t1;
COMMIT;
#
# NOWAIT.
# Take an exclusive lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# connection conn1.
# Try an exclusive lock,
# which conflicts and cannot immediately be taken.
LOCK TABLE t1 IN SHARE MODE NOWAIT;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# connection default.
# Commit.
COMMIT;
#
# Transactional table locks do not interfere with the global read lock.
# Take an exclusive lock on t1.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# connection conn1.
# Try an exclusive lock, which conflicts.
LOCK TABLE t1 IN EXCLUSIVE MODE;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# Can take the global read lock when an exclusive lock exist.
FLUSH TABLES WITH READ LOCK;
# Show that the global read lock exists.
LOCK TABLE t2 WRITE;
ERROR HY000: Can't execute the query because you have a conflicting read lock
# connection default.
# Can take an exclusive lock when the global read lock exists.
# Take an exclusive lock on t2.
LOCK TABLE t2 IN EXCLUSIVE MODE;
# connection conn1.
# Show that an exclusive lock on t1 exists.
LOCK TABLE t1 IN EXCLUSIVE MODE;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# Show that an exclusive lock on t2 exists.
LOCK TABLE t2 IN EXCLUSIVE MODE;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# Show that the global read lock exists.
LOCK TABLE t2 WRITE;
ERROR HY000: Can't execute the query because you have a conflicting read lock
# Release global read lock.
UNLOCK TABLES;
# Commit.
COMMIT;
# connection default.
UNLOCK TABLES;
# Commit.
COMMIT;
#
# Access conflict on INSERT.
# Take an share lock on t1.
LOCK TABLE t1 IN SHARE MODE;
# connection conn1.
SELECT GET_LOCK("mysqltest1", 10);
GET_LOCK("mysqltest1", 10)
1
# Try to insert a value,
# which must wait in background for the lock to go away.
INSERT INTO t1 VALUES (111);
## connection default.
## Wait in background until the insert times out and releases lock.
SELECT GET_LOCK("mysqltest1", 10);
# connection conn1.
# Wait for INSERT to timeout.
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
SELECT RELEASE_LOCK("mysqltest1");
RELEASE_LOCK("mysqltest1")
1
COMMIT;
# connection default.
GET_LOCK("mysqltest1", 10)
1
# Commit.
COMMIT;
# Show that the insert in conn1 failed.
SELECT * FROM t1;
c1
#
# Access conflict on UPDATE with exclusive lock.
# Insert a value.
INSERT INTO t1 VALUES (111);
COMMIT;
# connection conn1.
# Take an exclusive lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# connection default.
# Try a second exclusive lock, which fails due to the other lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# Try an update, which fails due to the exclusive lock.
UPDATE t1 SET c1= 111222;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# connection conn1.
# The exclusive table locker can still update.
UPDATE t1 SET c1= 111333;
# connection default.
# Select is allowed despite the table lock, but sees old data.
SELECT * FROM t1;
c1
111
# connection conn1.
# Commit.
COMMIT;
# connection default.
# It seems like the failed update began a transaction, so still old data.
SELECT * FROM t1;
c1
111
# Commit.
COMMIT;
# Now select sees current data.
SELECT * FROM t1;
c1
111333
TRUNCATE t1;
COMMIT;
#
# Access conflict on UPDATE with share lock.
# Insert a value.
INSERT INTO t1 VALUES (111);
COMMIT;
# connection conn1.
# Take a share lock.
LOCK TABLE t1 IN SHARE MODE;
# Update with a single share lock is possible.
UPDATE t1 SET c1= 111222;
# Commit to get rid of the row lock.
COMMIT;
# Take a share lock.
LOCK TABLE t1 IN SHARE MODE;
# connection default.
# An exclusive lock is not possible on a share lock.
LOCK TABLE t1 IN EXCLUSIVE MODE;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# More share locks are possible.
LOCK TABLE t1 IN SHARE MODE;
# Noone can update when multiple share locks exist.
UPDATE t1 SET c1= 111333;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# connection conn1.
# Noone can update when multiple share locks exist.
UPDATE t1 SET c1= 111444;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
COMMIT;
# connection default.
SELECT * FROM t1;
c1
111222
TRUNCATE t1;
COMMIT;
#
# LOCK TABLE is prohibited in stored procedure.
CREATE PROCEDURE lock_t1_excl()
LOCK TABLE t1 IN EXCLUSIVE MODE;
ERROR 0A000: LOCK is not allowed in stored procedures
#
# LOCK TABLE is prohibited in trigger.
CREATE TRIGGER t1_ai AFTER INSERT ON t1 FOR EACH ROW
LOCK TABLE t2 IN EXCLUSIVE MODE;
ERROR 0A000: LOCK is not allowed in stored procedures
#
# LOCK TABLE on a pre-locked table through a trigger.
# Create a trigger on t1 that updates t2.
CREATE TRIGGER t1_ai AFTER INSERT ON t1 FOR EACH ROW
BEGIN
UPDATE t2 SET c2= c2 + 111;
END//
# Take an exclusive lock on t1.
# This pre-locks t2 through the trigger.
LOCK TABLE t1 IN EXCLUSIVE MODE;
# connection conn1.
# Try to take an exclusive lock on t2,
# which is pre-locked through the trigger on t1.
LOCK TABLE t2 IN EXCLUSIVE MODE;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
COMMIT;
# connection default.
# Commit to release the lock.
COMMIT;
DROP TRIGGER t1_ai;
#
# LOCK TABLE on a pre-locked table through a view.
# Create a function that selects from t2.
CREATE FUNCTION count_t2() RETURNS INT
BEGIN
RETURN (SELECT COUNT(*) FROM t2);
END//
# Create a view with t1 and the function.
CREATE VIEW v1 AS SELECT COUNT(*), count_t2() FROM t1 GROUP BY 2;
# Take an exclusive lock on v1.
# This pre-locks t2 through the view.
LOCK TABLE v1 IN EXCLUSIVE MODE;
# connection conn1.
# Try to take an exclusive lock on t2,
# which is pre-locked through the function in v1.
LOCK TABLE t2 IN EXCLUSIVE MODE;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
COMMIT;
# connection default.
# Commit to release the lock.
COMMIT;
DROP VIEW v1;
DROP FUNCTION count_t2;
#
# Transactional LOCK TABLE by-passes pre-lock.
#
# Insert a value to t1 and t2 each.
INSERT INTO t1 VALUES (111);
INSERT INTO t2 VALUES (222);
COMMIT;
# Create a trigger on t1 that updates t2.
CREATE TRIGGER t1_ai AFTER INSERT ON t1 FOR EACH ROW
BEGIN
INSERT INTO t2 SELECT GET_LOCK("mysqltest1", 10);
UPDATE t2 SET c2= c2 + 111;
INSERT INTO t2 SELECT RELEASE_LOCK("mysqltest1");
END//
# Take an SQL lock which blocks the trigger.
SELECT GET_LOCK("mysqltest1", 10);
GET_LOCK("mysqltest1", 10)
1
# connection conn1.
# Insert into t1 to fire trigger. This waits on GET_LOCK.
INSERT INTO t1 VALUES(111222);
# connection default.
# Wait for the helper thread to sit on its lock.
# Take an exclusive lock.
LOCK TABLE t2 IN EXCLUSIVE MODE;
# Use the lock for insert.
INSERT INTO t2 VALUES (111333);
# Commit to release the lock again.
COMMIT;
# Release the SQL lock to let the trigger finish.
SELECT RELEASE_LOCK("mysqltest1");
RELEASE_LOCK("mysqltest1")
1
# connection conn1.
# Trigger succeeded.
# Commit.
COMMIT;
# connection default.
# Commit.
COMMIT;
# Show the results.
SELECT * FROM t1;
c1
111
111222
SELECT * FROM t2;
c2
333
111444
112
1
TRUNCATE t1;
TRUNCATE t2;
COMMIT;
DROP TRIGGER t1_ai;
#
# Non-transactional LOCK TABLE cannot by-passes pre-lock.
#
# Insert a value to t1 and t2 each.
INSERT INTO t1 VALUES (111);
INSERT INTO t2 VALUES (222);
COMMIT;
# Create a trigger on t1 that updates t2.
CREATE TRIGGER t1_ai AFTER INSERT ON t1 FOR EACH ROW
BEGIN
# This will time out. So use a small value.
INSERT INTO t2 SELECT GET_LOCK("mysqltest1", 1);
UPDATE t2 SET c2= c2 + 111;
INSERT INTO t2 SELECT RELEASE_LOCK("mysqltest1");
END//
# Take an SQL lock which blocks the trigger.
SELECT GET_LOCK("mysqltest1", 10);
GET_LOCK("mysqltest1", 10)
1
# connection conn1.
# Insert into t1 to fire trigger. This waits on GET_LOCK.
INSERT INTO t1 VALUES(111222);
# connection default.
# Wait for the helper thread to sit on its lock.
# Take a write lock. This waits until the trigger times out.
LOCK TABLE t2 WRITE;
# Use the lock for insert.
INSERT INTO t2 VALUES (111333);
# Release the lock again.
UNLOCK TABLES;
# Release the SQL lock.
SELECT RELEASE_LOCK("mysqltest1");
RELEASE_LOCK("mysqltest1")
1
# connection conn1.
# Trigger timed out.
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
# Commit.
COMMIT;
# connection default.
# Commit.
COMMIT;
# Show the results.
SELECT * FROM t1;
c1
111
SELECT * FROM t2;
c2
222
111333
TRUNCATE t1;
TRUNCATE t2;
COMMIT;
DROP TRIGGER t1_ai;
## Cleanup.
SET AUTOCOMMIT= 1;
UNLOCK TABLES;
DROP TABLE t1, t2;
show slave status;;
Slave_IO_State #
Master_Host 127.0.0.1
Master_User root
Master_Port MASTER_PORT
Connect_Retry 1
Master_Log_File master-bin.000001
Read_Master_Log_Pos #
Relay_Log_File #
Relay_Log_Pos #
Relay_Master_Log_File master-bin.000001
Slave_IO_Running Yes
Slave_SQL_Running Yes
Replicate_Do_DB
Replicate_Ignore_DB
Replicate_Do_Table
Replicate_Ignore_Table
Replicate_Wild_Do_Table
Replicate_Wild_Ignore_Table
Last_Errno 0
Last_Error
Skip_Counter 0
Exec_Master_Log_Pos #
Relay_Log_Space #
Until_Condition None
Until_Log_File
Until_Log_Pos 0
Master_SSL_Allowed No
Master_SSL_CA_File
Master_SSL_CA_Path
Master_SSL_Cert
Master_SSL_Cipher
Master_SSL_Key
Seconds_Behind_Master #
Master_SSL_Verify_Server_Cert No
Last_IO_Errno 0
Last_IO_Error
Last_SQL_Errno 0
Last_SQL_Error
|