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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

80
mysql-test/t/truncate_coverage.test
View File

@ -17,86 +17,6 @@ DROP TABLE IF EXISTS t1;
--echo # Bug#20667 - Truncate table fails for a write locked table
--echo #
########
# Attack wait_while_table_is_used(). Kill query while trying to
# upgrade MDL.
#
CREATE TABLE t1 (c1 INT);
INSERT INTO t1 VALUES (1);
#
# Acquire a shared metadata lock on table by opening HANDLER for it and wait.
# TRUNCATE shall block on this metadata lock.
# We can't use normal DML as such statements would also block LOCK TABLES.
#
--connect (con1, localhost, root,,)
HANDLER t1 OPEN;
#
# Get connection id of default connection.
# Lock the table and start TRUNCATE, which will block on MDL upgrade.
#
--connection default
let $ID= `SELECT @id := CONNECTION_ID()`;
LOCK TABLE t1 WRITE;
SET DEBUG_SYNC='mdl_upgrade_lock SIGNAL waiting';
send TRUNCATE TABLE t1;
#
# Get the default connection ID into a variable in an invisible statement.
# Kill the TRUNCATE query. This shall result in an error return
# from wait_while_table_is_used().
#
--connect (con2, localhost, root,,)
SET DEBUG_SYNC='now WAIT_FOR waiting';
let $invisible_assignment_in_select = `SELECT @id := $ID`;
KILL QUERY @id;
--disconnect con2
--connection default
--error ER_QUERY_INTERRUPTED
reap;
UNLOCK TABLES;
--connection con1
--echo # Release shared metadata lock by closing HANDLER.
HANDLER t1 CLOSE;
--disconnect con1
--connection default
DROP TABLE t1;
SET DEBUG_SYNC='RESET';
########
# Attack reopen_tables(). Remove form file.
#
CREATE TABLE t1 (c1 INT);
INSERT INTO t1 VALUES (1);
#
# Acquire a shared metadata lock on table by opening HANDLER for it and wait.
# TRUNCATE shall block on this metadata lock.
# We can't use normal DML as such statements would also block LOCK TABLES.
#
--connect (con1, localhost, root,,)
HANDLER t1 OPEN;
#
# Lock the table and start TRUNCATE, which will block on MDL upgrade.
#
--connection default
LOCK TABLE t1 WRITE;
SET DEBUG_SYNC='mdl_upgrade_lock SIGNAL waiting';
send TRUNCATE TABLE t1;
#
# Remove datafile.
# Commit to let TRUNCATE continue.
#
--connect (con2, localhost, root,,)
SET DEBUG_SYNC='now WAIT_FOR waiting';
--remove_file $MYSQLD_DATADIR/test/t1.frm
--disconnect con2
--connection con1
HANDLER t1 CLOSE;
--disconnect con1
--connection default
--error ER_NO_SUCH_TABLE
reap;
UNLOCK TABLES;
--error ER_BAD_TABLE_ERROR
DROP TABLE t1;
SET DEBUG_SYNC='RESET';
########
# Attack acquire_exclusive_locks(). Hold a global read lock.
# Non-LOCK TABLE case.
#