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MDEV-27962 Instant DDL downgrades the MDL when table is empty

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- Server incorrectly downgrading the MDL after prepare phase when
table is empty. mdl_exclusive_after_prepare is being set in
prepare phase only. But mdl_exclusive_after_prepare condition was
misplaced and checked before prepare phase by
commit d270525dfd and it is now
changed to check after prepare phase.

 - main.innodb_mysql_sync test case was changed to avoid locking
optimization when table is empty.
This commit is contained in:
Thirunarayanan Balathandayuthapani
2022-03-01 13:01:48 +05:30
parent 3c58cdd91d
commit 446ec64651
5 changed files with 54 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
mysql-test/main/innodb_mysql_sync.result
View File

@ -131,6 +131,7 @@ connection default;
DROP DATABASE db1;
# Test 2: Primary index (implicit), should block writes.
CREATE TABLE t1(a INT NOT NULL, b INT NOT NULL) engine=innodb;
INSERT INTO t1 VALUES(1, 2);
SET DEBUG_SYNC= "alter_table_inplace_after_lock_downgrade SIGNAL manage WAIT_FOR query";
# Sending:
ALTER TABLE t1 ADD UNIQUE INDEX(a), LOCK=SHARED;
@ -139,15 +140,16 @@ SET DEBUG_SYNC= "now WAIT_FOR manage";
USE test;
SELECT * FROM t1;
a b
1 2
# Sending:
UPDATE t1 SET a=NULL;
UPDATE t1 SET a=3;
connection con2;
# Waiting for SELECT to be blocked by the metadata lock on t1
SET DEBUG_SYNC= "now SIGNAL query";
connection default;
# Reaping: ALTER TABLE t1 ADD UNIQUE INDEX(a)
connection con1;
# Reaping: UPDATE t1 SET a=NULL
# Reaping: UPDATE t1 SET a=3
# Test 3: Primary index (explicit), should block writes.
connection default;
ALTER TABLE t1 DROP INDEX a;
@ -158,15 +160,16 @@ connection con1;
SET DEBUG_SYNC= "now WAIT_FOR manage";
SELECT * FROM t1;
a b
3 2
# Sending:
UPDATE t1 SET a=NULL;
UPDATE t1 SET a=4;
connection con2;
# Waiting for SELECT to be blocked by the metadata lock on t1
SET DEBUG_SYNC= "now SIGNAL query";
connection default;
# Reaping: ALTER TABLE t1 ADD PRIMARY KEY (a)
connection con1;
# Reaping: UPDATE t1 SET a=NULL
# Reaping: UPDATE t1 SET a=4
# Test 4: Secondary unique index, should not block reads.
connection default;
SET DEBUG_SYNC= "alter_table_inplace_after_lock_downgrade SIGNAL manage WAIT_FOR query";
@ -176,6 +179,7 @@ connection con1;
SET DEBUG_SYNC= "now WAIT_FOR manage";
SELECT * FROM t1;
a b
4 2
SET DEBUG_SYNC= "now SIGNAL query";
connection default;
# Reaping: ALTER TABLE t1 ADD UNIQUE (b)

13
mysql-test/main/innodb_mysql_sync.test
View File

@ -176,6 +176,7 @@ DROP DATABASE db1;
--echo # Test 2: Primary index (implicit), should block writes.
CREATE TABLE t1(a INT NOT NULL, b INT NOT NULL) engine=innodb;
INSERT INTO t1 VALUES(1, 2);
SET DEBUG_SYNC= "alter_table_inplace_after_lock_downgrade SIGNAL manage WAIT_FOR query";
--echo # Sending:
--send ALTER TABLE t1 ADD UNIQUE INDEX(a), LOCK=SHARED
@ -185,13 +186,13 @@ SET DEBUG_SYNC= "now WAIT_FOR manage";
USE test;
SELECT * FROM t1;
--echo # Sending:
--send UPDATE t1 SET a=NULL
--send UPDATE t1 SET a=3
connection con2;
--echo # Waiting for SELECT to be blocked by the metadata lock on t1
let $wait_condition= SELECT COUNT(*)= 1 FROM information_schema.processlist
WHERE state= 'Waiting for table metadata lock'
AND info='UPDATE t1 SET a=NULL';
AND info='UPDATE t1 SET a=3';
--source include/wait_condition.inc
SET DEBUG_SYNC= "now SIGNAL query";
@ -200,7 +201,7 @@ connection default;
--reap
connection con1;
--echo # Reaping: UPDATE t1 SET a=NULL
--echo # Reaping: UPDATE t1 SET a=3
--reap
--echo # Test 3: Primary index (explicit), should block writes.
@ -215,13 +216,13 @@ connection con1;
SET DEBUG_SYNC= "now WAIT_FOR manage";
SELECT * FROM t1;
--echo # Sending:
--send UPDATE t1 SET a=NULL
--send UPDATE t1 SET a=4
connection con2;
--echo # Waiting for SELECT to be blocked by the metadata lock on t1
let $wait_condition= SELECT COUNT(*)= 1 FROM information_schema.processlist
WHERE state= 'Waiting for table metadata lock'
AND info='UPDATE t1 SET a=NULL';
AND info='UPDATE t1 SET a=4';
--source include/wait_condition.inc
SET DEBUG_SYNC= "now SIGNAL query";
@ -230,7 +231,7 @@ connection default;
--reap
connection con1;
--echo # Reaping: UPDATE t1 SET a=NULL
--echo # Reaping: UPDATE t1 SET a=4
--reap
--echo # Test 4: Secondary unique index, should not block reads.

17
mysql-test/suite/innodb/r/instant_alter_debug.result
View File

@ -462,12 +462,27 @@ INSERT INTO t1 SET a=0, i=REPEAT('1', 10000);
ROLLBACK;
set DEBUG_SYNC='now SIGNAL go';
connection default;
disconnect con1;
SELECT * FROM t1;
a b c d e f g h i
1 2 3 4 5 6 7 8 test
DROP TABLE t1;
SET DEBUG_SYNC=RESET;
#
# MDEV-27962 Instant DDL downgrades the MDL when table is empty
#
CREATE TABLE t1(f1 INT NOT NULL, f2 INT NOT NULL)ENGINE=InnoDB;
SET DEBUG_SYNC="alter_table_inplace_after_lock_downgrade SIGNAL try_insert WAIT_FOR alter_progress";
ALTER TABLE t1 ADD INDEX(f1), ADD INDEX(f2);
connection con1;
SET SESSION lock_wait_timeout=1;
SET DEBUG_SYNC="now WAIT_FOR try_insert";
INSERT INTO t1 VALUES(1, 2);
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
SET DEBUG_SYNC="now SIGNAL alter_progress";
disconnect con1;
connection default;
DROP TABLE t1;
SET DEBUG_SYNC=reset;
# End of 10.4 tests
SET GLOBAL innodb_purge_rseg_truncate_frequency = @save_frequency;
SELECT variable_value-@old_instant instants

19
mysql-test/suite/innodb/t/instant_alter_debug.test
View File

@ -533,11 +533,28 @@ set DEBUG_SYNC='now SIGNAL go';
connection default;
reap;
disconnect con1;
SELECT * FROM t1;
DROP TABLE t1;
SET DEBUG_SYNC=RESET;
--echo #
--echo # MDEV-27962 Instant DDL downgrades the MDL when table is empty
--echo #
CREATE TABLE t1(f1 INT NOT NULL, f2 INT NOT NULL)ENGINE=InnoDB;
SET DEBUG_SYNC="alter_table_inplace_after_lock_downgrade SIGNAL try_insert WAIT_FOR alter_progress";
send ALTER TABLE t1 ADD INDEX(f1), ADD INDEX(f2);
connection con1;
SET SESSION lock_wait_timeout=1;
SET DEBUG_SYNC="now WAIT_FOR try_insert";
--error ER_LOCK_WAIT_TIMEOUT
INSERT INTO t1 VALUES(1, 2);
SET DEBUG_SYNC="now SIGNAL alter_progress";
disconnect con1;
connection default;
reap;
DROP TABLE t1;
SET DEBUG_SYNC=reset;
--echo # End of 10.4 tests
SET GLOBAL innodb_purge_rseg_truncate_frequency = @save_frequency;

10
sql/sql_table.cc
View File

@ -7716,16 +7716,15 @@ static bool mysql_inplace_alter_table(THD *thd,
lock for prepare phase under LOCK TABLES in the same way as when
exclusive lock is required for duration of the whole statement.
*/
if (!ha_alter_info->mdl_exclusive_after_prepare &&
(inplace_supported == HA_ALTER_INPLACE_EXCLUSIVE_LOCK ||
((inplace_supported == HA_ALTER_INPLACE_COPY_NO_LOCK ||
if (inplace_supported == HA_ALTER_INPLACE_EXCLUSIVE_LOCK ||
((inplace_supported == HA_ALTER_INPLACE_COPY_NO_LOCK ||
inplace_supported == HA_ALTER_INPLACE_COPY_LOCK ||
inplace_supported == HA_ALTER_INPLACE_NOCOPY_NO_LOCK ||
inplace_supported == HA_ALTER_INPLACE_NOCOPY_LOCK ||
inplace_supported == HA_ALTER_INPLACE_INSTANT) &&
(thd->locked_tables_mode == LTM_LOCK_TABLES ||
thd->locked_tables_mode == LTM_PRELOCKED_UNDER_LOCK_TABLES)) ||
alter_info->requested_lock == Alter_info::ALTER_TABLE_LOCK_EXCLUSIVE))
alter_info->requested_lock == Alter_info::ALTER_TABLE_LOCK_EXCLUSIVE)
{
if (wait_while_table_is_used(thd, table, HA_EXTRA_FORCE_REOPEN))
goto cleanup;
@ -7822,7 +7821,8 @@ static bool mysql_inplace_alter_table(THD *thd,
necessary only for prepare phase (unless we are not under LOCK TABLES) and
user has not explicitly requested exclusive lock.
*/
if ((inplace_supported == HA_ALTER_INPLACE_COPY_NO_LOCK ||
if (!ha_alter_info->mdl_exclusive_after_prepare &&
(inplace_supported == HA_ALTER_INPLACE_COPY_NO_LOCK ||
inplace_supported == HA_ALTER_INPLACE_COPY_LOCK ||
inplace_supported == HA_ALTER_INPLACE_NOCOPY_LOCK ||
inplace_supported == HA_ALTER_INPLACE_NOCOPY_NO_LOCK) &&