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Backport of revno: 2617.71.1

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Bug#42546 Backup: RESTORE fails, thinking it finds an existing table

The problem occured when a MDL locking conflict happened for a non-existent 
table between a CREATE and a INSERT statement. The code for CREATE 
interpreted this lock conflict to mean that the table existed, 
which meant that the statement failed when it should not have.
The problem could occur for CREATE TABLE, CREATE TABLE LIKE and
ALTER TABLE RENAME.

This patch fixes the problem for CREATE TABLE and CREATE TABLE LIKE.
It is based on code backported from the mysql-6.1-fk tree written
by Dmitry Lenev. CREATE now uses normal open_and_lock_tables() code 
to acquire exclusive locks. This means that for the test case in the bug 
description, CREATE will wait until INSERT completes so that it can 
get the exclusive lock. This resolves the reported bug.

The patch also prohibits CREATE TABLE and CREATE TABLE LIKE under 
LOCK TABLES. Note that this is an incompatible change and must 
be reflected in the documentation. Affected test cases have been
updated.

mdl_sync.test contains tests for CREATE TABLE and CREATE TABLE LIKE.

Fixing the issue for ALTER TABLE RENAME is beyond the scope of this
patch. ALTER TABLE cannot be prohibited from working under LOCK TABLES
as this could seriously impact customers and a proper fix would require
a significant rewrite.
This commit is contained in:
Jon Olav Hauglid
2009-12-10 11:53:20 +01:00
parent 6c25664eb3
commit b20a409c38
21 changed files with 465 additions and 415 deletions
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30
mysql-test/r/merge.result
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@ -1149,7 +1149,8 @@ SHOW CREATE TABLE t3;
ERROR 42S02: Table 'test.t3' doesn't exist
DROP TABLE t1, t2;
#
# CREATE ... LIKE
# Bug#37371 "CREATE TABLE LIKE merge loses UNION parameter"
# Demonstrate that this is no longer the case.
#
# 1. Create like.
CREATE TABLE t1 (c1 INT);
@ -1164,26 +1165,26 @@ SHOW CREATE TABLE t4;
Table Create Table
t4 CREATE TABLE `t4` (
`c1` int(11) DEFAULT NULL
) ENGINE=MRG_MyISAM DEFAULT CHARSET=latin1
) ENGINE=MRG_MyISAM DEFAULT CHARSET=latin1 INSERT_METHOD=LAST UNION=(`t1`,`t2`)
INSERT INTO t4 VALUES (4);
ERROR HY000: Table 't4' is read only
DROP TABLE t4;
#
# 1. Create like with locked tables.
LOCK TABLES t3 WRITE, t2 WRITE, t1 WRITE;
CREATE TABLE t4 LIKE t3;
ERROR HY000: Table 't4' was not locked with LOCK TABLES
SHOW CREATE TABLE t4;
ERROR HY000: Table 't4' was not locked with LOCK TABLES
INSERT INTO t4 VALUES (4);
ERROR HY000: Table 't4' was not locked with LOCK TABLES
CREATE TEMPORARY TABLE t4 LIKE t3;
SHOW CREATE TABLE t4;
ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist
INSERT INTO t4 VALUES (4);
ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist
UNLOCK TABLES;
SHOW CREATE TABLE t4;
Table Create Table
t4 CREATE TABLE `t4` (
`c1` int(11) DEFAULT NULL
) ENGINE=MRG_MyISAM DEFAULT CHARSET=latin1
INSERT INTO t4 VALUES (4);
ERROR HY000: Table 't4' is read only
ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist
DROP TABLE t4;
#
# Rename child.
@ -1210,6 +1211,7 @@ c1
1
2
3
4
RENAME TABLE t2 TO t5;
SELECT * FROM t3 ORDER BY c1;
ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist
@ -1219,6 +1221,7 @@ c1
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2
3
4
#
# 3. Normal rename with locked tables.
LOCK TABLES t1 WRITE, t2 WRITE, t3 WRITE;
@ -1227,6 +1230,7 @@ c1
1
2
3
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RENAME TABLE t2 TO t5;
ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
SELECT * FROM t3 ORDER BY c1;
@ -1234,6 +1238,7 @@ c1
1
2
3
4
RENAME TABLE t5 TO t2;
ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
SELECT * FROM t3 ORDER BY c1;
@ -1241,6 +1246,7 @@ c1
1
2
3
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UNLOCK TABLES;
#
# 4. Alter table rename.
@ -1253,6 +1259,7 @@ c1
1
2
3
4
#
# 5. Alter table rename with locked tables.
LOCK TABLES t1 WRITE, t2 WRITE, t3 WRITE;
@ -1268,6 +1275,7 @@ c1
1
2
3
4
#
# Rename parent.
#
@ -1278,6 +1286,7 @@ c1
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2
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RENAME TABLE t3 TO t5;
ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
SELECT * FROM t3 ORDER BY c1;
@ -1285,6 +1294,7 @@ c1
1
2
3
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RENAME TABLE t5 TO t3;
ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
SELECT * FROM t3 ORDER BY c1;
@ -1292,6 +1302,7 @@ c1
1
2
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#
# 5. Alter table rename with locked tables.
ALTER TABLE t3 RENAME TO t5;
@ -1306,6 +1317,7 @@ c1
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DROP TABLE t1, t2, t3;
#
# Drop locked tables.