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MDEV-7660 - MySQL WL#6671 "Improve scalability by not using thr_lock.c locks

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for InnoDB tables"

Don't use thr_lock.c locks for InnoDB tables. Below is list of changes that
were needed to implement this:
- HANDLER OPEN acquireis MDL_SHARED_READ instead of MDL_SHARED
- HANDLER READ calls external_lock() even if SE is not going to be locked by
  THR_LOCK
- InnoDB lock wait timeouts are now honored which are much shorter by default
  than server lock wait timeouts (1 year vs 50 seconds)
- with @@autocommit= 1 LOCK TABLES disables autocommit implicitely, though
  user still sees @@autocommt= 1
- the above starts implicit transaction
- transactions started by LOCK TABLES are now rolled back on disconnect
  (previously everything was committed due to autocommit)
- transactions started by LOCK TABLES are now rolled back by ROLLBACK
  (previously everything was committed due to autocommit)
- it is now impossible to change BINLOG_FORMAT under LOCK TABLES (at least
  to statement) due to running transaction
- LOCK TABLES WRITE is additionally handled by MDL
- ...in contrast LOCK TABLES READ protection against DML is pure InnoDB
- combining transactional and non-transactional tables under LOCK TABLES
  may cause rolled back changes in transactional table and "committed"
  changes in non-transactional table
- user may disable innodb_table_locks, which will cause LOCK TABLES to be
  noop basically

Removed tests for BUG#45143 and BUG#55930 which cover InnoDB + THR_LOCK. To
operate properly these tests require code flow to go through THR_LOCK debug
sync points, which is not the case after this patch. These tests are removed
by WL#6671 as well. An alternative is to port them to different storage engine.
This commit is contained in:
Sergey Vojtovich
2016-05-06 13:44:07 +04:00
parent e2d6912609
commit d665e79c5b
31 changed files with 151 additions and 1034 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
mysql-test/r/partition_debug_sync.result
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@ -64,29 +64,3 @@ disconnect con1;
connection default;
SET DEBUG_SYNC= 'RESET';
End of 5.1 tests
#
# Coverage test for non pruned ha_partition::store_lock()
#
CREATE TABLE t1 (a int) ENGINE = InnoDB;
CREATE TABLE t2 (a int PRIMARY KEY)
ENGINE = InnoDB PARTITION BY HASH (a) PARTITIONS 3;
HANDLER t1 OPEN;
connect con1, localhost, root,,;
LOCK TABLES t1 WRITE, t2 READ;
connection default;
SET DEBUG_SYNC="wait_for_lock SIGNAL locking";
INSERT INTO t2 VALUES (1), (2), (3);
connection con1;
SET DEBUG_SYNC="now WAIT_FOR locking";
ALTER TABLE t1 ADD COLUMN b int;
connection default;
ERROR HY000: Wait on a lock was aborted due to a pending exclusive lock
SELECT 1;
1
1
connection con1;
UNLOCK TABLES;
disconnect con1;
connection default;
SET DEBUG_SYNC = 'RESET';
DROP TABLE t1, t2;