MDEV-7660 - MySQL WL#6671 "Improve scalability by not using thr_lock.c locksbb-10.2-mdev7660

            for InnoDB tables"

Don't use thr_lock.c locks for InnoDB tables.

Let HANDLER READ call external_lock() even if SE is not going to be locked by
THR_LOCK. This fixes at least main.implicit_commit failure.

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.

31 files changed, 180 insertions, 1033 deletions

diff --git a/mysql-test/r/innodb_mysql_lock.result b/mysql-test/r/innodb_mysql_lock.result
index a7f45d355f1..6d2eef2e62e 100644
--- a/mysql-test/r/innodb_mysql_lock.result
+++ b/mysql-test/r/innodb_mysql_lock.result
@@ -95,8 +95,6 @@ LOCK TABLES t1 READ;
 SELECT release_lock('bug42147_lock');
 release_lock('bug42147_lock')
 1
-connection default;
-connection con2;
 UNLOCK TABLES;
 connection default;
 disconnect con2;
diff --git a/mysql-test/r/lock_sync.result b/mysql-test/r/lock_sync.result
index f075262c3db..5eae1af7982 100644
--- a/mysql-test/r/lock_sync.result
+++ b/mysql-test/r/lock_sync.result
@@ -338,6 +338,7 @@ Success: 'load data infile '../../std_data/rpl_loaddata.dat' into table t2 (@a,
 # 2.8 REPLACE with a subquery.
 # 
 # Same is true for this statement as well.
+# Suppress warnings for REPLACE ... SELECT
 connection default;
 Success: 'replace into t2 select i+5 from t1' doesn't allow concurrent inserts into 't1'.
 connection default;
@@ -704,87 +705,6 @@ disconnect con1;
 disconnect con2;
 set @@global.concurrent_insert= @old_concurrent_insert;
 #
-# Test for bug #45143 "All connections hang on concurrent ALTER TABLE".
-#
-# Concurrent execution of statements which required weak write lock
-# (TL_WRITE_ALLOW_WRITE) on several instances of the same table and
-# statements which tried to acquire stronger write lock (TL_WRITE,
-# TL_WRITE_ALLOW_READ) on this table might have led to deadlock.
-drop table if exists t1;
-drop view if exists v1;
-# Create auxiliary connections used through the test.
-connect  con_bug45143_1,localhost,root,,test,,;
-connect  con_bug45143_3,localhost,root,,test,,;
-connect  con_bug45143_2,localhost,root,,test,,;
-connection default;
-# Reset DEBUG_SYNC facility before using it.
-set debug_sync= 'RESET';
-# Turn off logging so calls to locking subsystem performed
-# for general_log table won't interfere with our test.
-set @old_general_log = @@global.general_log;
-set @@global.general_log= OFF;
-create table t1 (i int) engine=InnoDB;
-# We have to use view in order to make LOCK TABLES avoid
-# acquiring SNRW metadata lock on table.
-create view v1 as select * from t1;
-insert into t1 values (1);
-# Prepare user lock which will be used for resuming execution of
-# the first statement after it acquires TL_WRITE_ALLOW_WRITE lock.
-select get_lock("lock_bug45143_wait", 0);
-get_lock("lock_bug45143_wait", 0)
-1
-connection con_bug45143_1;
-# Sending:
-insert into t1 values (get_lock("lock_bug45143_wait", 100));;
-connection con_bug45143_2;
-# Wait until the above INSERT takes TL_WRITE_ALLOW_WRITE lock on 't1'
-# and then gets blocked on user lock 'lock_bug45143_wait'.
-# Ensure that upcoming SELECT waits after acquiring TL_WRITE_ALLOW_WRITE
-# lock for the first instance of 't1'.
-set debug_sync='thr_multi_lock_after_thr_lock SIGNAL parked WAIT_FOR go';
-# Sending:
-select count(*) > 0 from t1 as a, t1 as b for update;;
-connection con_bug45143_3;
-# Wait until the above SELECT ... FOR UPDATE is blocked after
-# acquiring lock for the the first instance of 't1'.
-set debug_sync= 'now WAIT_FOR parked';
-# Send LOCK TABLE statement which will try to get TL_WRITE lock on 't1':
-lock table v1 write;;
-connection default;
-# Wait until this LOCK TABLES statement starts waiting for table lock.
-# Allow SELECT ... FOR UPDATE to resume.
-# Since it already has TL_WRITE_ALLOW_WRITE lock on the first instance
-# of 't1' it should be able to get lock on the second instance without
-# waiting, even although there is another thread which has such lock
-# on this table and also there is a thread waiting for a TL_WRITE on it.
-set debug_sync= 'now SIGNAL go';
-connection con_bug45143_2;
-# Reap SELECT ... FOR UPDATE
-count(*) > 0
-1
-connection default;
-# Resume execution of the INSERT statement.
-select release_lock("lock_bug45143_wait");
-release_lock("lock_bug45143_wait")
-1
-connection con_bug45143_1;
-# Reap INSERT statement.
-# In Statement and Mixed replication mode we get here "Unsafe 
-# for binlog" warnings. In row mode there are no warnings.
-# Hide the discrepancy.
-connection con_bug45143_3;
-# Reap LOCK TABLES statement.
-unlock tables;
-connection default;
-# Do clean-up.
-disconnect con_bug45143_1;
-disconnect con_bug45143_2;
-disconnect con_bug45143_3;
-set debug_sync= 'RESET';
-set @@global.general_log= @old_general_log;
-drop view v1;
-drop table t1;
-#
 # Bug#50821 Deadlock between LOCK TABLES and ALTER TABLE
 #
 DROP TABLE IF EXISTS t1, t2;
@@ -827,44 +747,6 @@ connection default;
 DROP EVENT e2;
 SET DEBUG_SYNC="RESET";
 #
-# Bug#55930 Assertion `thd->transaction.stmt.is_empty() ||
-#           thd->in_sub_stmt || (thd->state..
-#
-DROP TABLE IF EXISTS t1;
-CREATE TABLE t1(a INT) engine=InnoDB;
-INSERT INTO t1 VALUES (1), (2);
-connect  con1, localhost, root;
-connect  con2, localhost, root;
-connection con1;
-SET SESSION lock_wait_timeout= 1;
-SET DEBUG_SYNC= 'ha_admin_open_ltable SIGNAL opti_recreate WAIT_FOR opti_analyze';
-# Sending:
-OPTIMIZE TABLE t1;
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR opti_recreate';
-SET DEBUG_SYNC= 'after_lock_tables_takes_lock SIGNAL thrlock WAIT_FOR release_thrlock';
-# Sending:
-INSERT INTO t1 VALUES (3);
-connection default;
-SET DEBUG_SYNC= 'now WAIT_FOR thrlock';
-SET DEBUG_SYNC= 'now SIGNAL opti_analyze';
-connection con1;
-# Reaping: OPTIMIZE TABLE t1
-Table	Op	Msg_type	Msg_text
-test.t1	optimize	note	Table does not support optimize, doing recreate + analyze instead
-test.t1	optimize	error	Lock wait timeout exceeded; try restarting transaction
-test.t1	optimize	status	Operation failed
-Warnings:
-Error	1205	Lock wait timeout exceeded; try restarting transaction
-SET DEBUG_SYNC= 'now SIGNAL release_thrlock';
-disconnect con1;
-connection con2;
-# Reaping: INSERT INTO t1 VALUES (3)
-disconnect con2;
-connection default;
-DROP TABLE t1;
-SET DEBUG_SYNC= 'RESET';
-#
 # Bug#57130 crash in Item_field::print during SHOW CREATE TABLE or VIEW
 #
 DROP TABLE IF EXISTS t1;
diff --git a/mysql-test/r/lock_tables_lost_commit.result b/mysql-test/r/lock_tables_lost_commit.result
index 769e9734c7a..394ef0a9d1c 100644
--- a/mysql-test/r/lock_tables_lost_commit.result
+++ b/mysql-test/r/lock_tables_lost_commit.result
@@ -9,7 +9,6 @@ disconnect con1;
 connection con2;
 SELECT * FROM t1;
 a
-10
 DROP TABLE t1;
 connection default;
 disconnect con2;
diff --git a/mysql-test/r/mdl_sync.result b/mysql-test/r/mdl_sync.result
index 865e874f63e..1e285650c77 100644
--- a/mysql-test/r/mdl_sync.result
+++ b/mysql-test/r/mdl_sync.result
@@ -76,10 +76,6 @@ ERROR 42000: Key column 'not_exist' doesn't exist in table
 # lock.
 alter table t1 add primary key (c1);
 ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
-# Check that SNRW lock is compatible with S lock.
-lock table t1 write;
-insert into t1 values (1);
-unlock tables;
 # Check that X lock is incompatible with S lock.
 # Sending:
 rename table t1 to t2;;
@@ -117,29 +113,6 @@ connection mdl_con1;
 alter table t1 drop column c2;
 # 
 connection default;
-handler t1 open;
-# 
-connection mdl_con1;
-# Check that upgrade from SNRW to X is blocked by presence of S lock.
-lock table t1 write;
-# Sending:
-alter table t1 add column c2 int;;
-# 
-connection mdl_con2;
-# Check that the above upgrade of SNRW to X in ALTER TABLE is blocked
-# because of S lock.
-# 
-connection default;
-# Unblock ALTER TABLE.
-handler t1 close;
-# 
-connection mdl_con1;
-# Reaping ALTER TABLE.
-# Restore the original state of the things.
-alter table t1 drop column c2;
-unlock tables;
-# 
-connection default;
 #
 # 2) Acquire SH (shared high-priority) lock on the table.
 #    We have to involve DEBUG_SYNC facility for this as usually
@@ -160,7 +133,7 @@ column_name
 c1
 select count(*) from t1;
 count(*)
-3
+2
 insert into t1 values (1);
 # Check that SU lock is compatible with it. To do this use ALTER TABLE
 # which will fail when constructing .frm and thus obtaining SU metadata
@@ -258,7 +231,7 @@ connection default;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # 
 connection mdl_con1;
 # Check that S, SH, SR and SW locks are compatible with it.
@@ -270,7 +243,7 @@ column_name
 c1
 select count(*) from t1;
 count(*)
-3
+2
 insert into t1 values (1);
 # Check that SU lock is compatible with it. To do this use ALTER TABLE
 # which will fail when constructing .frm and thus obtaining SU metadata
@@ -300,7 +273,7 @@ connection default;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # 
 connection mdl_con1;
 # Check that X lock is incompatible with SR lock.
@@ -323,7 +296,7 @@ connection default;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # 
 connection mdl_con1;
 # Check that upgrade from SNW to X is blocked by presence of SR lock.
@@ -453,7 +426,7 @@ column_name
 c1
 select count(*) from t1;
 count(*)
-5
+4
 delete from t1 limit 1;
 # Check that SU lock is incompatible with SU lock.
 # Sending:
@@ -549,7 +522,7 @@ column_name
 c1
 select count(*) from t1;
 count(*)
-5
+4
 # Check that SW lock is incompatible with SNW lock.
 # Sending:
 delete from t1 limit 2;;
@@ -658,8 +631,6 @@ lock table t1 write;
 # 
 connection mdl_con1;
 # Check that S and SH locks are compatible with it.
-handler t1 open;
-handler t1 close;
 select column_name from information_schema.columns where
 table_schema='test' and table_name='t1';
 column_name
@@ -676,7 +647,7 @@ unlock tables;
 connection mdl_con1;
 # Reaping SELECT.
 count(*)
-4
+3
 # 
 connection default;
 lock table t1 write;
@@ -847,7 +818,7 @@ ERROR 42S01: Table 't2' already exists
 connection mdl_con1;
 # Reaping SELECT.
 count(*)
-4
+3
 # 
 connection mdl_con2;
 # Prepare for blocking RENAME TABLE.
@@ -996,7 +967,7 @@ column_name
 c1
 select count(*) from t1;
 count(*)
-4
+3
 # Check that SW is incompatible with pending SNW
 # Sending:
 delete from t1 limit 1;;
@@ -1025,7 +996,7 @@ connection mdl_con2;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # 
 connection default;
 # Add pending SNRW lock.
@@ -1035,8 +1006,6 @@ lock table t1 write;;
 connection mdl_con1;
 # Check that LOCK TABLE is waiting with pending SNRW lock.
 # Check that S and SH locks are compatible with pending SNRW
-handler t1 open t;
-handler t close;
 select column_name from information_schema.columns where
 table_schema='test' and table_name='t1';
 column_name
@@ -1057,14 +1026,14 @@ unlock tables;
 connection mdl_con1;
 # Reaping SELECT.
 count(*)
-3
+2
 # Restore pending SNRW lock.
 # 
 connection mdl_con2;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # 
 connection default;
 # Sending:
@@ -1093,7 +1062,7 @@ connection mdl_con2;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection default;
 # Sending:
@@ -1126,7 +1095,7 @@ connection mdl_con2;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection default;
 # Add pending X lock.
@@ -1162,7 +1131,7 @@ connection mdl_con2;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection default;
 # Add pending X lock.
@@ -1187,14 +1156,14 @@ ERROR 42S01: Table 't2' already exists
 connection mdl_con1;
 # Reaping SELECT.
 count(*)
-4
+3
 # Restore pending X lock.
 # 
 connection mdl_con2;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection default;
 # Add pending X lock.
@@ -1224,7 +1193,7 @@ connection mdl_con2;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # 
 connection default;
 # Add pending X lock.
@@ -1299,7 +1268,7 @@ connection default;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # 
 connection mdl_con1;
 # Create an active SNW lock on t2.
@@ -1321,7 +1290,7 @@ commit;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # Sending:
 insert into t2 values (1);;
 # 
@@ -1347,7 +1316,7 @@ commit;
 begin;
 select count(*) from t1;
 count(*)
-3
+2
 # 
 connection mdl_con1;
 # Create an active SNW lock on t1.
@@ -1360,7 +1329,7 @@ set debug_sync= 'now WAIT_FOR locked';
 # We should still be able to get SR lock without waiting.
 select count(*) from t1;
 count(*)
-3
+2
 # Since the above ALTER TABLE is not upgrading SNW lock to X by waiting
 # for SW lock we won't create deadlock.
 # So the below INSERT should not end-up with ER_LOCK_DEADLOCK error.
@@ -1397,7 +1366,7 @@ connection default;
 # We should still be able to get both SW and SR locks without waiting.
 select count(*) from t1;
 count(*)
-5
+4
 delete from t1 limit 1;
 # Unblock ALTER TABLE.
 commit;
@@ -1416,7 +1385,7 @@ connection default;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con2;
 # Start transaction which will prevent SNW -> X upgrade from
@@ -1454,7 +1423,7 @@ commit;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con2;
 # Start transaction which will prevent SNW -> X upgrade from
@@ -1493,7 +1462,7 @@ commit;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con1;
 # Create SNW lock pending upgrade to X.
@@ -1505,7 +1474,7 @@ connection default;
 # Check that transaction is still able to acquire SR lock.
 select count(*) from t1;
 count(*)
-4
+3
 # Waiting trying to acquire SW lock will cause deadlock and
 # therefore should cause an error.
 delete from t1 limit 1;
@@ -1526,7 +1495,7 @@ connection default;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con1;
 lock table t2 write;
@@ -1551,7 +1520,7 @@ commit;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con1;
 lock table t2 write;
@@ -1580,7 +1549,7 @@ commit;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con1;
 # Sending:
@@ -1591,7 +1560,7 @@ connection default;
 # Check that another instance of SR lock is granted without waiting.
 select count(*) from t1;
 count(*)
-4
+3
 # Attempt to wait for SW lock will lead to deadlock, thus
 # the below statement should end with ER_LOCK_DEADLOCK error.
 delete from t1 limit 1;
@@ -1620,7 +1589,7 @@ connection default;
 # and errors.
 select count(*) from t1;
 count(*)
-3
+2
 insert into t1 values (1, 1);
 # Unblock LOCK TABLES.
 commit;
@@ -1639,7 +1608,7 @@ connection default;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con2;
 # Start transaction which will prevent X lock from going away
@@ -1677,7 +1646,7 @@ rename table t3 to t2;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con2;
 # Start transaction which will prevent X lock from going away
@@ -1721,7 +1690,7 @@ rename table t3 to t2;
 begin;
 select count(*) from t1;
 count(*)
-4
+3
 # 
 connection mdl_con1;
 # Sending:
@@ -1732,7 +1701,7 @@ connection default;
 # Check that another instance of SR lock is granted without waiting.
 select count(*) from t1;
 count(*)
-4
+3
 # Attempt to wait for SW lock will lead to deadlock, thus
 # the below statement should end with ER_LOCK_DEADLOCK error.
 delete from t1 limit 1;
@@ -1761,7 +1730,7 @@ connection default;
 # and errors.
 select count(*) from t1;
 count(*)
-3
+2
 insert into t1 values (1, 1);
 # Unblock RENAME TABLE.
 commit;
@@ -1778,149 +1747,6 @@ disconnect mdl_con3;
 set debug_sync= 'RESET';
 drop table t1, t2;
 #
-# Additional coverage for some scenarios in which not quite
-# correct use of S metadata locks by HANDLER statement might
-# have caused deadlocks.
-#
-drop table if exists t1, t2;
-connect handler_con1,localhost,root,,;
-connect handler_con2,localhost,root,,;
-connection default;
-create table t1 (i int);
-create table t2 (j int);
-insert into t1 values (1);
-#
-# First, check scenario in which we upgrade SNRW lock to X lock
-# on a table while having HANDLER READ trying to acquire TL_READ
-# on the same table.
-#
-handler t1 open;
-# 
-connection handler_con1;
-lock table t1 write;
-# Upgrade SNRW to X lock.
-# Sending:
-alter table t1 add column j int;;
-# 
-connection handler_con2;
-# Wait until ALTER is blocked during upgrade.
-# 
-connection default;
-# The below statement should not cause deadlock.
-handler t1 read first;;
-# 
-connection handler_con1;
-# Reap ALTER TABLE.
-unlock tables;
-# 
-connection default;
-# Reap HANDLER READ.
-i	j
-1	NULL
-handler t1 close;
-#
-# Now, check scenario in which upgrade of SNRW lock to X lock
-# can be blocked by HANDLER which is open in connection currently
-# waiting to get table-lock owned by connection doing upgrade.
-#
-handler t1 open;
-# 
-connection handler_con1;
-lock table t1 write, t2 read;
-# 
-connection default;
-# Execute statement which will be blocked on table-level lock
-# owned by connection 'handler_con1'.
-# Sending:
-insert into t2 values (1);;
-# 
-connection handler_con1;
-# Wait until INSERT is blocked on table-level lock.
-# Sending 'alter table t1 drop column j'. It should not cause
-# deadlock.
-alter table t1 drop column j;
-connection handler_con2;
-# Wait until ALTER is blocked during upgrade.
-# 
-connection default;
-# Reap INSERT.
-ERROR HY000: Wait on a lock was aborted due to a pending exclusive lock
-handler t1 close;
-#
-connection handler_con1;
-# Reaping 'alter table t1 drop column j'
-unlock tables;
-connection default;
-# Then, check the scenario in which upgrade of SNRW lock to X
-# lock is blocked by HANDLER which is open in connection currently
-# waiting to get SW lock on the same table.
-#
-handler t1 open;
-# 
-connection handler_con1;
-lock table t1 write;
-# 
-connection default;
-# The below insert should be blocked because active SNRW lock on 't1'.
-# Sending:
-insert into t1 values (1);;
-# 
-connection handler_con1;
-# Wait until INSERT is blocked because of SNRW lock.
-# The below ALTER TABLE will be blocked because of presence of HANDLER.
-# Sending:
-alter table t1 add column j int;;
-# 
-connection default;
-# INSERT should be chosen as victim for resolving deadlock.
-# Reaping INSERT.
-ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
-# Close HANDLER to unblock ALTER TABLE.
-handler t1 close;
-# 
-connection handler_con1;
-# Reaping ALTER TABLE.
-unlock tables;
-# 
-connection default;
-#
-# Finally, test in which upgrade of SNRW lock to X lock is blocked
-# by HANDLER which is open in connection currently waiting to get
-# SR lock on the table on which lock is upgraded.
-#
-handler t1 open;
-# 
-connection handler_con1;
-lock table t1 write, t2 write;
-# 
-connection default;
-# The below insert should be blocked because active SNRW lock on 't1'.
-# Sending:
-insert into t2 values (1);;
-# 
-connection handler_con1;
-# Wait until INSERT is blocked because of SNRW lock.
-# The below ALTER TABLE will be blocked because of presence of HANDLER.
-# Sending:
-alter table t1 drop column j;;
-# 
-connection default;
-# INSERT should be chosen as victim for resolving deadlock.
-# Reaping INSERT.
-ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
-# Close HANDLER to unblock ALTER TABLE.
-handler t1 close;
-# 
-connection handler_con1;
-# Reaping ALTER TABLE.
-unlock tables;
-# 
-connection default;
-# Clean-up.
-disconnect handler_con1;
-disconnect handler_con2;
-drop tables t1, t2;
-#
 # Test coverage for basic deadlock detection in metadata
 # locking subsystem.
 #
diff --git a/mysql-test/r/partition_debug_sync.result b/mysql-test/r/partition_debug_sync.result
index 971bc63e2e7..b79385686b7 100644
--- a/mysql-test/r/partition_debug_sync.result
+++ b/mysql-test/r/partition_debug_sync.result
@@ -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;
diff --git a/mysql-test/r/partition_explicit_prune.result b/mysql-test/r/partition_explicit_prune.result
index 0cf9bde225c..1272ff8c5fc 100644
--- a/mysql-test/r/partition_explicit_prune.result
+++ b/mysql-test/r/partition_explicit_prune.result
@@ -281,7 +281,7 @@ UNLOCK TABLES;
 SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
 WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
 VARIABLE_NAME	VARIABLE_VALUE
-HANDLER_COMMIT	2
+HANDLER_COMMIT	3
 HANDLER_READ_RND_NEXT	54
 HANDLER_TMP_WRITE	75
 HANDLER_WRITE	2
@@ -440,7 +440,7 @@ UNLOCK TABLES;
 SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
 WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
 VARIABLE_NAME	VARIABLE_VALUE
-HANDLER_COMMIT	5
+HANDLER_COMMIT	6
 HANDLER_READ_FIRST	3
 HANDLER_READ_NEXT	4
 HANDLER_READ_RND_NEXT	108
@@ -665,7 +665,7 @@ UNLOCK TABLES;
 SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
 WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
 VARIABLE_NAME	VARIABLE_VALUE
-HANDLER_COMMIT	5
+HANDLER_COMMIT	6
 HANDLER_DELETE	2
 HANDLER_READ_FIRST	1
 HANDLER_READ_KEY	3
@@ -758,7 +758,7 @@ UNLOCK TABLES;
 SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
 WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
 VARIABLE_NAME	VARIABLE_VALUE
-HANDLER_COMMIT	2
+HANDLER_COMMIT	3
 HANDLER_READ_RND_NEXT	54
 HANDLER_TMP_WRITE	75
 HANDLER_WRITE	10
@@ -953,7 +953,7 @@ UNLOCK TABLES;
 SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
 WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
 VARIABLE_NAME	VARIABLE_VALUE
-HANDLER_COMMIT	3
+HANDLER_COMMIT	4
 HANDLER_DELETE	1
 HANDLER_READ_KEY	2
 HANDLER_READ_RND	2
@@ -1039,7 +1039,7 @@ UNLOCK TABLES;
 SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
 WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
 VARIABLE_NAME	VARIABLE_VALUE
-HANDLER_COMMIT	3
+HANDLER_COMMIT	4
 HANDLER_DELETE	2
 HANDLER_READ_KEY	3
 HANDLER_READ_NEXT	1
diff --git a/mysql-test/r/truncate_coverage.result b/mysql-test/r/truncate_coverage.result
index 95e649912e5..078de1ef3ab 100644
--- a/mysql-test/r/truncate_coverage.result
+++ b/mysql-test/r/truncate_coverage.result
@@ -6,48 +6,6 @@ DROP TABLE IF EXISTS t1;
 CREATE TABLE t1 (c1 INT);
 INSERT INTO t1 VALUES (1);
 connect  con1, localhost, root,,;
-HANDLER t1 OPEN;
-connection default;
-LOCK TABLE t1 WRITE;
-SET DEBUG_SYNC='mdl_upgrade_lock SIGNAL waiting';
-TRUNCATE TABLE t1;
-connect  con2, localhost, root,,;
-SET DEBUG_SYNC='now WAIT_FOR waiting';
-KILL QUERY @id;
-disconnect con2;
-connection default;
-ERROR 70100: Query execution was interrupted
-UNLOCK TABLES;
-connection con1;
-# Release shared metadata lock by closing HANDLER.
-HANDLER t1 CLOSE;
-disconnect con1;
-connection default;
-DROP TABLE t1;
-SET DEBUG_SYNC='RESET';
-CREATE TABLE t1 (c1 INT);
-INSERT INTO t1 VALUES (1);
-connect  con1, localhost, root,,;
-HANDLER t1 OPEN;
-connection default;
-LOCK TABLE t1 WRITE;
-SET DEBUG_SYNC='mdl_upgrade_lock SIGNAL waiting';
-TRUNCATE TABLE t1;
-connect  con2, localhost, root,,;
-SET DEBUG_SYNC='now WAIT_FOR waiting';
-disconnect con2;
-connection con1;
-HANDLER t1 CLOSE;
-disconnect con1;
-connection default;
-ERROR 42S02: Table 'test.t1' doesn't exist
-UNLOCK TABLES;
-DROP TABLE t1;
-ERROR 42S02: Unknown table 'test.t1'
-SET DEBUG_SYNC='RESET';
-CREATE TABLE t1 (c1 INT);
-INSERT INTO t1 VALUES (1);
-connect  con1, localhost, root,,;
 START TRANSACTION;
 INSERT INTO t1 VALUES (2);
 connection default;
diff --git a/mysql-test/suite/handler/aria.result b/mysql-test/suite/handler/aria.result
index b8ed1fd98c8..6b02ac9b085 100644
--- a/mysql-test/suite/handler/aria.result
+++ b/mysql-test/suite/handler/aria.result
@@ -545,7 +545,6 @@ optimize table t1;
 connection default;
 handler t1 read next;
 c1
-1
 handler t1 close;
 connection con2;
 Table	Op	Msg_type	Msg_text
@@ -1296,19 +1295,27 @@ commit;
 # an open HANDLER, ER_LOCK_DEADLOCK is reported.
 #
 create table t1 (a int, key a(a));
-create  table t2 like t1;
 handler t1 open;
 connection con1;
-lock table t1 write, t2 write;
+select get_lock('lock1', 10);
+get_lock('lock1', 10)
+1
 connection default;
-drop table t2;
+select get_lock('lock1', 10);
 connection con2;
-# Waiting for 'drop table t2' to get blocked...
+# Waiting for 'select get_lock('lock1', 10)' to get blocked...
 connection con1;
 drop table t1;
 ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
-unlock tables;
+select release_lock('lock1');
+release_lock('lock1')
+1
 connection default;
+get_lock('lock1', 10)
+1
+select release_lock('lock1');
+release_lock('lock1')
+1
 # Demonstrate that there is no deadlock with FLUSH TABLE,
 # even though it is waiting for the other table to go away
 create table t2 like t1;
@@ -1347,6 +1354,10 @@ handler t1 read a next;
 a
 1
 # Unblock 'lock tables t1 write'.
+select * from t1;
+a
+1
+2
 commit;
 connection con1;
 # Reap 'lock tables t1 write'.
@@ -1516,10 +1527,6 @@ handler t1 read a last;
 a	b
 7	7
 commit;
-connection con1;
-# Demonstrate that the HANDLER doesn't hold MDL_SHARED_WRITE.
-lock table t1 write;
-unlock tables;
 connection default;
 handler t1 read a prev;
 a	b
diff --git a/mysql-test/suite/handler/handler.inc b/mysql-test/suite/handler/handler.inc
index a4ab5f1ed32..2432ff13e55 100644
--- a/mysql-test/suite/handler/handler.inc
+++ b/mysql-test/suite/handler/handler.inc
@@ -1054,24 +1054,24 @@ commit;
 --echo # an open HANDLER, ER_LOCK_DEADLOCK is reported.
 --echo #
 create table t1 (a int, key a(a));
-create  table t2 like t1;
 handler t1 open;
 connection con1;
-lock table t1 write, t2 write;
+select get_lock('lock1', 10);
 connection default;
-send drop table t2;
+send select get_lock('lock1', 10);
 connection con2;
---echo # Waiting for 'drop table t2' to get blocked...
+--echo # Waiting for 'select get_lock('lock1', 10)' to get blocked...
 let $wait_condition=select count(*)=1 from information_schema.processlist
-                    where state='Waiting for table metadata lock' and
-                          info='drop table t2';
+                    where state='User lock' and
+                          info='select get_lock(\'lock1\', 10)';
 --source include/wait_condition.inc
 connection con1;
 --error ER_LOCK_DEADLOCK
 drop table t1;
-unlock tables;
+select release_lock('lock1');
 connection default;
 reap;
+select release_lock('lock1');
 
 --echo # Demonstrate that there is no deadlock with FLUSH TABLE,
 --echo # even though it is waiting for the other table to go away
@@ -1118,6 +1118,7 @@ connection default;
 handler t1 read a next;
 
 --echo # Unblock 'lock tables t1 write'.
+select * from t1; # Release MDL_SHARED_READ held by HANDLER
 commit;
 
 connection con1;
@@ -1132,7 +1133,7 @@ connection con1;
 --echo # Waiting for 'handler t1 read a next' to get blocked...
 let $wait_condition=
   select count(*) = 1 from information_schema.processlist
-  where state = "Waiting for table level lock" and
+  where state = "Waiting for table metadata lock" and
         info = "handler t1 read a next";
 --source include/wait_condition.inc
 
@@ -1259,10 +1260,6 @@ handler t1 read a last;
 insert into t1 (a, b) values (7, 7);
 handler t1 read a last;
 commit;
-connection con1;
---echo # Demonstrate that the HANDLER doesn't hold MDL_SHARED_WRITE.
-lock table t1 write;
-unlock tables;
 connection default;
 handler t1 read a prev;
 handler t1 close;
diff --git a/mysql-test/suite/handler/heap.result b/mysql-test/suite/handler/heap.result
index 70dcefe4ff3..fc42e43f710 100644
--- a/mysql-test/suite/handler/heap.result
+++ b/mysql-test/suite/handler/heap.result
@@ -545,7 +545,6 @@ optimize table t1;
 connection default;
 handler t1 read next;
 c1
-1
 handler t1 close;
 connection con2;
 Table	Op	Msg_type	Msg_text
@@ -1296,19 +1295,27 @@ commit;
 # an open HANDLER, ER_LOCK_DEADLOCK is reported.
 #
 create table t1 (a int, key a(a));
-create  table t2 like t1;
 handler t1 open;
 connection con1;
-lock table t1 write, t2 write;
+select get_lock('lock1', 10);
+get_lock('lock1', 10)
+1
 connection default;
-drop table t2;
+select get_lock('lock1', 10);
 connection con2;
-# Waiting for 'drop table t2' to get blocked...
+# Waiting for 'select get_lock('lock1', 10)' to get blocked...
 connection con1;
 drop table t1;
 ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
-unlock tables;
+select release_lock('lock1');
+release_lock('lock1')
+1
 connection default;
+get_lock('lock1', 10)
+1
+select release_lock('lock1');
+release_lock('lock1')
+1
 # Demonstrate that there is no deadlock with FLUSH TABLE,
 # even though it is waiting for the other table to go away
 create table t2 like t1;
@@ -1347,6 +1354,10 @@ handler t1 read a next;
 a
 1
 # Unblock 'lock tables t1 write'.
+select * from t1;
+a
+1
+2
 commit;
 connection con1;
 # Reap 'lock tables t1 write'.
@@ -1516,10 +1527,6 @@ handler t1 read a last;
 a	b
 7	7
 commit;
-connection con1;
-# Demonstrate that the HANDLER doesn't hold MDL_SHARED_WRITE.
-lock table t1 write;
-unlock tables;
 connection default;
 handler t1 read a prev;
 a	b
diff --git a/mysql-test/suite/handler/innodb.result b/mysql-test/suite/handler/innodb.result
index 102237617fd..80e8ed679a9 100644
--- a/mysql-test/suite/handler/innodb.result
+++ b/mysql-test/suite/handler/innodb.result
@@ -1299,19 +1299,27 @@ commit;
 # an open HANDLER, ER_LOCK_DEADLOCK is reported.
 #
 create table t1 (a int, key a(a));
-create  table t2 like t1;
 handler t1 open;
 connection con1;
-lock table t1 write, t2 write;
+select get_lock('lock1', 10);
+get_lock('lock1', 10)
+1
 connection default;
-drop table t2;
+select get_lock('lock1', 10);
 connection con2;
-# Waiting for 'drop table t2' to get blocked...
+# Waiting for 'select get_lock('lock1', 10)' to get blocked...
 connection con1;
 drop table t1;
 ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
-unlock tables;
+select release_lock('lock1');
+release_lock('lock1')
+1
 connection default;
+get_lock('lock1', 10)
+1
+select release_lock('lock1');
+release_lock('lock1')
+1
 # Demonstrate that there is no deadlock with FLUSH TABLE,
 # even though it is waiting for the other table to go away
 create table t2 like t1;
@@ -1350,6 +1358,10 @@ handler t1 read a next;
 a
 1
 # Unblock 'lock tables t1 write'.
+select * from t1;
+a
+1
+2
 commit;
 connection con1;
 # Reap 'lock tables t1 write'.
@@ -1519,10 +1531,6 @@ handler t1 read a last;
 a	b
 7	7
 commit;
-connection con1;
-# Demonstrate that the HANDLER doesn't hold MDL_SHARED_WRITE.
-lock table t1 write;
-unlock tables;
 connection default;
 handler t1 read a prev;
 a	b
diff --git a/mysql-test/suite/handler/interface.result b/mysql-test/suite/handler/interface.result
index 4d5a385df0f..a4ac32c16b4 100644
--- a/mysql-test/suite/handler/interface.result
+++ b/mysql-test/suite/handler/interface.result
@@ -272,24 +272,6 @@ handler t1 read a next;
 ERROR 42S02: Unknown table 't1' in HANDLER
 connect con1,localhost,root,,;
 connect con2,localhost,root,,;
-connection default;
-drop table if exists t1;
-# First test case which is supposed trigger the execution
-# path on which problem was discovered.
-create table t1 (a int not null);
-insert into t1 values (1);
-handler t1 open;
-connection con1;
-lock table t1 write;
-alter table t1 engine=csv;
-connection con2;
-connection default;
-handler t1 read a next;
-ERROR HY000: Storage engine CSV of the table `test`.`t1` doesn't have this option
-handler t1 close;
-connection con1;
-unlock tables;
-drop table t1;
 # Now test case which was reported originally but which no longer
 # triggers execution path which has caused the problem.
 connection default;
diff --git a/mysql-test/suite/handler/interface.test b/mysql-test/suite/handler/interface.test
index a82412799eb..2f576c9b291 100644
--- a/mysql-test/suite/handler/interface.test
+++ b/mysql-test/suite/handler/interface.test
@@ -298,32 +298,6 @@ handler t1 read a next;
 connect(con1,localhost,root,,);
 connect(con2,localhost,root,,);
 
-connection default;
---disable_warnings
-drop table if exists t1;
---enable_warnings
---echo # First test case which is supposed trigger the execution
---echo # path on which problem was discovered.
-create table t1 (a int not null);
-insert into t1 values (1);
-handler t1 open;
-connection con1;
-lock table t1 write;
-send alter table t1 engine=csv;
-connection con2;
-let $wait_condition=
-  select count(*) = 1 from information_schema.processlist
-  where state = "Waiting for table metadata lock" and
-        info = "alter table t1 engine=csv";
---source include/wait_condition.inc
-connection default;
---error ER_ILLEGAL_HA
-handler t1 read a next;
-handler t1 close;
-connection con1;
---reap
-unlock tables;
-drop table t1;
 --echo # Now test case which was reported originally but which no longer
 --echo # triggers execution path which has caused the problem.
 connection default;
diff --git a/mysql-test/suite/handler/myisam.result b/mysql-test/suite/handler/myisam.result
index fca75f3b7a6..90e1767a1f3 100644
--- a/mysql-test/suite/handler/myisam.result
+++ b/mysql-test/suite/handler/myisam.result
@@ -545,7 +545,6 @@ optimize table t1;
 connection default;
 handler t1 read next;
 c1
-1
 handler t1 close;
 connection con2;
 Table	Op	Msg_type	Msg_text
@@ -1296,19 +1295,27 @@ commit;
 # an open HANDLER, ER_LOCK_DEADLOCK is reported.
 #
 create table t1 (a int, key a(a));
-create  table t2 like t1;
 handler t1 open;
 connection con1;
-lock table t1 write, t2 write;
+select get_lock('lock1', 10);
+get_lock('lock1', 10)
+1
 connection default;
-drop table t2;
+select get_lock('lock1', 10);
 connection con2;
-# Waiting for 'drop table t2' to get blocked...
+# Waiting for 'select get_lock('lock1', 10)' to get blocked...
 connection con1;
 drop table t1;
 ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
-unlock tables;
+select release_lock('lock1');
+release_lock('lock1')
+1
 connection default;
+get_lock('lock1', 10)
+1
+select release_lock('lock1');
+release_lock('lock1')
+1
 # Demonstrate that there is no deadlock with FLUSH TABLE,
 # even though it is waiting for the other table to go away
 create table t2 like t1;
@@ -1347,6 +1354,10 @@ handler t1 read a next;
 a
 1
 # Unblock 'lock tables t1 write'.
+select * from t1;
+a
+1
+2
 commit;
 connection con1;
 # Reap 'lock tables t1 write'.
@@ -1516,10 +1527,6 @@ handler t1 read a last;
 a	b
 7	7
 commit;
-connection con1;
-# Demonstrate that the HANDLER doesn't hold MDL_SHARED_WRITE.
-lock table t1 write;
-unlock tables;
 connection default;
 handler t1 read a prev;
 a	b
diff --git a/mysql-test/suite/rpl/r/rpl_switch_stm_row_mixed.result b/mysql-test/suite/rpl/r/rpl_switch_stm_row_mixed.result
index 6c709945111..3b5f67efe78 100644
--- a/mysql-test/suite/rpl/r/rpl_switch_stm_row_mixed.result
+++ b/mysql-test/suite/rpl/r/rpl_switch_stm_row_mixed.result
@@ -410,6 +410,7 @@ LOCK TABLES t11 WRITE;
 SET SESSION BINLOG_FORMAT=ROW;
 INSERT INTO t11 VALUES('Several Species of Small Furry Animals Gathered Together in a Cave and Grooving With a Pict');
 SET SESSION BINLOG_FORMAT=STATEMENT;
+ERROR HY000: Cannot modify @@session.binlog_format inside a transaction
 INSERT INTO t11 VALUES('Careful With That Axe, Eugene');
 UNLOCK TABLES;
 SELECT * FROM t11;
diff --git a/mysql-test/suite/rpl/t/rpl_switch_stm_row_mixed.test b/mysql-test/suite/rpl/t/rpl_switch_stm_row_mixed.test
index 575fdb2e89d..e5e2f7a381d 100644
--- a/mysql-test/suite/rpl/t/rpl_switch_stm_row_mixed.test
+++ b/mysql-test/suite/rpl/t/rpl_switch_stm_row_mixed.test
@@ -524,6 +524,7 @@ CREATE TABLE t11 (song VARCHAR(255));
 LOCK TABLES t11 WRITE;
 SET SESSION BINLOG_FORMAT=ROW;
 INSERT INTO t11 VALUES('Several Species of Small Furry Animals Gathered Together in a Cave and Grooving With a Pict');
+--error ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_BINLOG_FORMAT
 SET SESSION BINLOG_FORMAT=STATEMENT;
 INSERT INTO t11 VALUES('Careful With That Axe, Eugene');
 UNLOCK TABLES;
diff --git a/mysql-test/t/innodb_mysql_lock.test b/mysql-test/t/innodb_mysql_lock.test
index cb57c092e40..85ba41860df 100644
--- a/mysql-test/t/innodb_mysql_lock.test
+++ b/mysql-test/t/innodb_mysql_lock.test
@@ -150,14 +150,16 @@ let $wait_condition=
 --source include/wait_condition.inc
 LOCK TABLES t1 READ;
 SELECT release_lock('bug42147_lock');
+let $wait_condition=
+  SELECT COUNT(*) > 0 FROM information_schema.processlist
+  WHERE state = 'executing'
+  AND info = 'INSERT INTO t1 SELECT get_lock(\'bug42147_lock\', 60)';
+--source include/wait_condition.inc
+UNLOCK TABLES;
 
 connection default;
 --reap
 
-connection con2;
-UNLOCK TABLES;
-
-connection default;
 disconnect con2;
 DROP TABLE t1;
 
diff --git a/mysql-test/t/lock_sync.test b/mysql-test/t/lock_sync.test
index c090e3a1d93..07c16acc72a 100644
--- a/mysql-test/t/lock_sync.test
+++ b/mysql-test/t/lock_sync.test
@@ -406,6 +406,12 @@ let $restore_table= t2;
 --echo # 2.8 REPLACE with a subquery.
 --echo # 
 --echo # Same is true for this statement as well.
+
+--echo # Suppress warnings for REPLACE ... SELECT
+--disable_query_log
+call mtr.add_suppression("Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT");
+--enable_query_log
+
 let $statement= replace into t2 select i+5 from t1;
 let $restore_table= t2;
 --source include/check_no_concurrent_insert.inc
@@ -873,116 +879,6 @@ set @@global.concurrent_insert= @old_concurrent_insert;
 
 
 --echo #
---echo # Test for bug #45143 "All connections hang on concurrent ALTER TABLE".
---echo #
---echo # Concurrent execution of statements which required weak write lock
---echo # (TL_WRITE_ALLOW_WRITE) on several instances of the same table and
---echo # statements which tried to acquire stronger write lock (TL_WRITE,
---echo # TL_WRITE_ALLOW_READ) on this table might have led to deadlock.
-#
-# Suppress warnings for INSERTs that use get_lock().
-#
-disable_query_log;
-call mtr.add_suppression("Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT");
-enable_query_log;
-
---disable_warnings
-drop table if exists t1;
-drop view if exists v1;
---enable_warnings
---echo # Create auxiliary connections used through the test.
-connect (con_bug45143_1,localhost,root,,test,,);
-connect (con_bug45143_3,localhost,root,,test,,);
-connect (con_bug45143_2,localhost,root,,test,,);
-connection default;
---echo # Reset DEBUG_SYNC facility before using it.
-set debug_sync= 'RESET';
---echo # Turn off logging so calls to locking subsystem performed
---echo # for general_log table won't interfere with our test.
-set @old_general_log = @@global.general_log;
-set @@global.general_log= OFF;
-
-create table t1 (i int) engine=InnoDB;
---echo # We have to use view in order to make LOCK TABLES avoid
---echo # acquiring SNRW metadata lock on table.
-create view v1 as select * from t1;
-insert into t1 values (1);
---echo # Prepare user lock which will be used for resuming execution of
---echo # the first statement after it acquires TL_WRITE_ALLOW_WRITE lock.
-select get_lock("lock_bug45143_wait", 0);
-
-connection con_bug45143_1;
---echo # Sending:
---send insert into t1 values (get_lock("lock_bug45143_wait", 100));
-
-connection con_bug45143_2;
---echo # Wait until the above INSERT takes TL_WRITE_ALLOW_WRITE lock on 't1'
---echo # and then gets blocked on user lock 'lock_bug45143_wait'.
-let $wait_condition= select count(*)= 1 from information_schema.processlist
-                       where state= 'User lock' and
-                             info='insert into t1 values (get_lock("lock_bug45143_wait", 100))';
---source include/wait_condition.inc
---echo # Ensure that upcoming SELECT waits after acquiring TL_WRITE_ALLOW_WRITE
---echo # lock for the first instance of 't1'.
-set debug_sync='thr_multi_lock_after_thr_lock SIGNAL parked WAIT_FOR go';
---echo # Sending:
---send select count(*) > 0 from t1 as a, t1 as b for update;
-
-connection con_bug45143_3;
---echo # Wait until the above SELECT ... FOR UPDATE is blocked after
---echo # acquiring lock for the the first instance of 't1'.
-set debug_sync= 'now WAIT_FOR parked';
---echo # Send LOCK TABLE statement which will try to get TL_WRITE lock on 't1':
---send lock table v1 write;
-
-connection default;
---echo # Wait until this LOCK TABLES statement starts waiting for table lock.
-let $wait_condition= select count(*)= 1 from information_schema.processlist
-                       where state= 'Waiting for table level lock' and
-                             info='lock table v1 write';
---source include/wait_condition.inc
---echo # Allow SELECT ... FOR UPDATE to resume.
---echo # Since it already has TL_WRITE_ALLOW_WRITE lock on the first instance
---echo # of 't1' it should be able to get lock on the second instance without
---echo # waiting, even although there is another thread which has such lock
---echo # on this table and also there is a thread waiting for a TL_WRITE on it.
-set debug_sync= 'now SIGNAL go';
-
-connection con_bug45143_2;
---echo # Reap SELECT ... FOR UPDATE
---reap
-
-connection default;
---echo # Resume execution of the INSERT statement.
-select release_lock("lock_bug45143_wait");
-
-connection con_bug45143_1;
---echo # Reap INSERT statement.
---echo # In Statement and Mixed replication mode we get here "Unsafe 
---echo # for binlog" warnings. In row mode there are no warnings.
---echo # Hide the discrepancy.
---disable_warnings
---reap
---enable_warnings
-
-
-connection con_bug45143_3;
---echo # Reap LOCK TABLES statement.
---reap
-unlock tables;
-
-connection default;
---echo # Do clean-up.
-disconnect con_bug45143_1;
-disconnect con_bug45143_2;
-disconnect con_bug45143_3;
-set debug_sync= 'RESET';
-set @@global.general_log= @old_general_log;
-drop view v1;
-drop table t1;
-
-
---echo #
 --echo # Bug#50821 Deadlock between LOCK TABLES and ALTER TABLE
 --echo #
 
@@ -1051,55 +947,6 @@ SET DEBUG_SYNC="RESET";
 
 
 --echo #
---echo # Bug#55930 Assertion `thd->transaction.stmt.is_empty() ||
---echo #           thd->in_sub_stmt || (thd->state..
---echo #
-
---disable_warnings
-DROP TABLE IF EXISTS t1;
---enable_warnings
-
-CREATE TABLE t1(a INT) engine=InnoDB;
-INSERT INTO t1 VALUES (1), (2);
-
-connect (con1, localhost, root);
-connect (con2, localhost, root);
-
-connection con1;
-SET SESSION lock_wait_timeout= 1;
-SET DEBUG_SYNC= 'ha_admin_open_ltable SIGNAL opti_recreate WAIT_FOR opti_analyze';
---echo # Sending:
---send OPTIMIZE TABLE t1
-
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR opti_recreate';
-SET DEBUG_SYNC= 'after_lock_tables_takes_lock SIGNAL thrlock WAIT_FOR release_thrlock';
---echo # Sending:
---send INSERT INTO t1 VALUES (3)
-
-connection default;
-SET DEBUG_SYNC= 'now WAIT_FOR thrlock';
-SET DEBUG_SYNC= 'now SIGNAL opti_analyze';
-
-connection con1;
---echo # Reaping: OPTIMIZE TABLE t1
---reap
-SET DEBUG_SYNC= 'now SIGNAL release_thrlock';
-disconnect con1;
---source include/wait_until_disconnected.inc
-
-connection con2;
---echo # Reaping: INSERT INTO t1 VALUES (3)
---reap
-disconnect con2;
---source include/wait_until_disconnected.inc
-
-connection default;
-DROP TABLE t1;
-SET DEBUG_SYNC= 'RESET';
-
-
---echo #
 --echo # Bug#57130 crash in Item_field::print during SHOW CREATE TABLE or VIEW
 --echo #
 
diff --git a/mysql-test/t/mdl_sync.test b/mysql-test/t/mdl_sync.test
index 0b6d6f58013..4aa191d3dfc 100644
--- a/mysql-test/t/mdl_sync.test
+++ b/mysql-test/t/mdl_sync.test
@@ -119,10 +119,6 @@ alter table t1 add index (not_exist);
 --echo # lock.
 --error ER_DUP_ENTRY
 alter table t1 add primary key (c1);
---echo # Check that SNRW lock is compatible with S lock.
-lock table t1 write;
-insert into t1 values (1);
-unlock tables;
 --echo # Check that X lock is incompatible with S lock.
 --echo # Sending:
 --send rename table t1 to t2;
@@ -172,35 +168,6 @@ connection mdl_con1;
 alter table t1 drop column c2;
 --echo # 
 connection default;
-handler t1 open;
---echo # 
-connection mdl_con1;
---echo # Check that upgrade from SNRW to X is blocked by presence of S lock.
-lock table t1 write;
---echo # Sending:
---send alter table t1 add column c2 int;
---echo # 
-connection mdl_con2;
---echo # Check that the above upgrade of SNRW to X in ALTER TABLE is blocked
---echo # because of S lock.
-let $wait_condition=
-  select count(*) = 1 from information_schema.processlist
-  where state = "Waiting for table metadata lock" and
-        info = "alter table t1 add column c2 int";
---source include/wait_condition.inc
---echo # 
-connection default;
---echo # Unblock ALTER TABLE.
-handler t1 close;
---echo # 
-connection mdl_con1;
---echo # Reaping ALTER TABLE.
---reap
---echo # Restore the original state of the things.
-alter table t1 drop column c2;
-unlock tables;
---echo # 
-connection default;
 --echo #
 --echo # 2) Acquire SH (shared high-priority) lock on the table.
 --echo #    We have to involve DEBUG_SYNC facility for this as usually
@@ -797,8 +764,6 @@ lock table t1 write;
 --echo # 
 connection mdl_con1;
 --echo # Check that S and SH locks are compatible with it.
-handler t1 open;
-handler t1 close;
 select column_name from information_schema.columns where
   table_schema='test' and table_name='t1';
 --echo # Check that SR lock is incompatible with SNRW lock.
@@ -1293,8 +1258,6 @@ where state = "Waiting for table metadata lock" and
       info = "lock table t1 write";
 --source include/wait_condition.inc
 --echo # Check that S and SH locks are compatible with pending SNRW
-handler t1 open t;
-handler t close;
 select column_name from information_schema.columns where
   table_schema='test' and table_name='t1';
 --echo # Check that SR is incompatible with pending SNRW
@@ -2162,190 +2125,6 @@ disconnect mdl_con3;
 set debug_sync= 'RESET';
 drop table t1, t2;
 
-
---echo #
---echo # Additional coverage for some scenarios in which not quite
---echo # correct use of S metadata locks by HANDLER statement might
---echo # have caused deadlocks.
---echo #
---disable_warnings
-drop table if exists t1, t2;
---enable_warnings
-connect(handler_con1,localhost,root,,);
-connect(handler_con2,localhost,root,,);
-connection default;
-create table t1 (i int);
-create table t2 (j int);
-insert into t1 values (1);
-
---echo #
---echo # First, check scenario in which we upgrade SNRW lock to X lock
---echo # on a table while having HANDLER READ trying to acquire TL_READ
---echo # on the same table.
---echo #
-handler t1 open;
---echo # 
-connection handler_con1;
-lock table t1 write;
---echo # Upgrade SNRW to X lock.
---echo # Sending:
---send alter table t1 add column j int;
---echo # 
-connection handler_con2;
---echo # Wait until ALTER is blocked during upgrade.
-let $wait_condition=
-  select count(*) = 1 from information_schema.processlist
-  where state = "Waiting for table metadata lock" and
-        info = "alter table t1 add column j int";
---source include/wait_condition.inc
---echo # 
-connection default;
---echo # The below statement should not cause deadlock.
---send handler t1 read first;
---echo # 
-connection handler_con1;
---echo # Reap ALTER TABLE.
---reap
-unlock tables;
---echo # 
-connection default;
---echo # Reap HANDLER READ.
---reap
-handler t1 close;
-
---echo #
---echo # Now, check scenario in which upgrade of SNRW lock to X lock
---echo # can be blocked by HANDLER which is open in connection currently
---echo # waiting to get table-lock owned by connection doing upgrade.
---echo #
-handler t1 open;
---echo # 
-connection handler_con1;
-lock table t1 write, t2 read;
---echo # 
-connection default;
---echo # Execute statement which will be blocked on table-level lock
---echo # owned by connection 'handler_con1'.
---echo # Sending:
---send insert into t2 values (1);
---echo # 
-connection handler_con1;
---echo # Wait until INSERT is blocked on table-level lock.
-let $wait_condition=
-  select count(*) = 1 from information_schema.processlist
-  where state = "Waiting for table level lock" and
-        info = "insert into t2 values (1)";
---source include/wait_condition.inc
---echo # Sending 'alter table t1 drop column j'. It should not cause
---echo # deadlock.
-send alter table t1 drop column j;
-connection handler_con2;
---echo # Wait until ALTER is blocked during upgrade.
-let $wait_condition=
-  select count(*) = 1 from information_schema.processlist
-  where state = "Waiting for table metadata lock" and
-        info = "alter table t1 drop column j";
---source include/wait_condition.inc
---echo # 
-connection default;
---echo # Reap INSERT.
---error ER_LOCK_ABORTED
---reap
-handler t1 close;
---echo #
-connection handler_con1;
---echo # Reaping 'alter table t1 drop column j'
---reap
-unlock tables;
-connection default;
-
---echo # Then, check the scenario in which upgrade of SNRW lock to X
---echo # lock is blocked by HANDLER which is open in connection currently
---echo # waiting to get SW lock on the same table.
---echo #
-handler t1 open;
---echo # 
-connection handler_con1;
-lock table t1 write;
---echo # 
-connection default;
---echo # The below insert should be blocked because active SNRW lock on 't1'.
---echo # Sending:
---send insert into t1 values (1);
---echo # 
-connection handler_con1;
---echo # Wait until INSERT is blocked because of SNRW lock.
-let $wait_condition=
-  select count(*) = 1 from information_schema.processlist
-  where state = "Waiting for table metadata lock" and
-        info = "insert into t1 values (1)";
---source include/wait_condition.inc
---echo # The below ALTER TABLE will be blocked because of presence of HANDLER.
---echo # Sending:
---send alter table t1 add column j int;
---echo # 
-connection default;
---echo # INSERT should be chosen as victim for resolving deadlock.
---echo # Reaping INSERT.
---error ER_LOCK_DEADLOCK
---reap
---echo # Close HANDLER to unblock ALTER TABLE.
-handler t1 close;
---echo # 
-connection handler_con1;
---echo # Reaping ALTER TABLE.
---reap
-unlock tables;
---echo # 
-connection default;
-
---echo #
---echo # Finally, test in which upgrade of SNRW lock to X lock is blocked
---echo # by HANDLER which is open in connection currently waiting to get
---echo # SR lock on the table on which lock is upgraded.
---echo #
-handler t1 open;
---echo # 
-connection handler_con1;
-lock table t1 write, t2 write;
---echo # 
-connection default;
---echo # The below insert should be blocked because active SNRW lock on 't1'.
---echo # Sending:
---send insert into t2 values (1);
---echo # 
-connection handler_con1;
---echo # Wait until INSERT is blocked because of SNRW lock.
-let $wait_condition=
-  select count(*) = 1 from information_schema.processlist
-  where state = "Waiting for table metadata lock" and
-        info = "insert into t2 values (1)";
---source include/wait_condition.inc
---echo # The below ALTER TABLE will be blocked because of presence of HANDLER.
---echo # Sending:
---send alter table t1 drop column j;
---echo # 
-connection default;
---echo # INSERT should be chosen as victim for resolving deadlock.
---echo # Reaping INSERT.
---error ER_LOCK_DEADLOCK
---reap
---echo # Close HANDLER to unblock ALTER TABLE.
-handler t1 close;
---echo # 
-connection handler_con1;
---echo # Reaping ALTER TABLE.
---reap
-unlock tables;
---echo # 
-connection default;
-
---echo # Clean-up.
-disconnect handler_con1;
-disconnect handler_con2;
-drop tables t1, t2;
-
-
 --echo #
 --echo # Test coverage for basic deadlock detection in metadata
 --echo # locking subsystem.
diff --git a/mysql-test/t/partition_debug_sync.test b/mysql-test/t/partition_debug_sync.test
index 11af9b06cdd..f085ea3fb83 100644
--- a/mysql-test/t/partition_debug_sync.test
+++ b/mysql-test/t/partition_debug_sync.test
@@ -82,43 +82,3 @@ connection default;
 SET DEBUG_SYNC= 'RESET';
 
 --echo End of 5.1 tests
-
---echo #
---echo # Coverage test for non pruned ha_partition::store_lock()
---echo #
-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";
-send INSERT INTO t2 VALUES (1), (2), (3);
-
-connection con1;
-SET DEBUG_SYNC="now WAIT_FOR locking";
-
-send ALTER TABLE t1 ADD COLUMN b int;
-
-connection default;
---error ER_LOCK_ABORTED
---reap
-
-SELECT 1;
-
-connection con1;
---reap
-
-UNLOCK TABLES;
---disconnect con1
-
-connection default;
-SET DEBUG_SYNC = 'RESET';
-
-DROP TABLE t1, t2;
diff --git a/mysql-test/t/truncate_coverage.test b/mysql-test/t/truncate_coverage.test
index 0834f7a3eca..3351ce84232 100644
--- a/mysql-test/t/truncate_coverage.test
+++ b/mysql-test/t/truncate_coverage.test
@@ -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.
 #
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index d3832a7068e..d4045c804d7 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -2150,6 +2150,11 @@ Locked_tables_list::unlock_locked_tables(THD *thd)
     request for metadata locks and TABLE_LIST elements.
   */
   reset();
+  if (thd->variables.option_bits & OPTION_AUTOCOMMIT)
+  {
+    thd->variables.option_bits&= ~(OPTION_NOT_AUTOCOMMIT);
+    thd->server_status|= SERVER_STATUS_AUTOCOMMIT;
+  }
 }
 
 
diff --git a/sql/sql_handler.cc b/sql/sql_handler.cc
index 95417c73c74..405e7ce8c38 100644
--- a/sql/sql_handler.cc
+++ b/sql/sql_handler.cc
@@ -282,7 +282,7 @@ bool mysql_ha_open(THD *thd, TABLE_LIST *tables, SQL_HANDLER *reopen)
     back-off for such locks.
   */
   tables->mdl_request.init(MDL_key::TABLE, tables->db, tables->table_name,
-                           MDL_SHARED, MDL_TRANSACTION);
+                           MDL_SHARED_READ, MDL_TRANSACTION);
   mdl_savepoint= thd->mdl_context.mdl_savepoint();
 
   /* for now HANDLER can be used only for real TABLES */
@@ -750,11 +750,12 @@ retry:
   tables->table= table;                         // This is used by fix_fields
   table->pos_in_table_list= tables;
 
-  if (handler->lock->lock_count > 0)
+  if (handler->lock->table_count > 0)
   {
     int lock_error;
 
-    handler->lock->locks[0]->type= handler->lock->locks[0]->org_type;
+    if (handler->lock->lock_count > 0)
+      handler->lock->locks[0]->type= handler->lock->locks[0]->org_type;
 
     /* save open_tables state */
     TABLE* backup_open_tables= thd->open_tables;
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index ddb5e2744cb..ed7cb1f4bd8 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -4792,7 +4792,8 @@ end_with_restore_list:
     if (lock_tables_precheck(thd, all_tables))
       goto error;
 
-    thd->variables.option_bits|= OPTION_TABLE_LOCK;
+    thd->variables.option_bits|= OPTION_TABLE_LOCK | OPTION_NOT_AUTOCOMMIT;
+    thd->server_status&= ~SERVER_STATUS_AUTOCOMMIT;
 
     res= lock_tables_open_and_lock_tables(thd, all_tables);
 
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 604beec6f78..aa9f0c2962f 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -18917,7 +18917,6 @@ free_share(
 	mysql_mutex_unlock(&innobase_share_mutex);
 }
 
-#if 0
 /*********************************************************************//**
 Returns number of THR_LOCK locks used for one instance of InnoDB table.
 InnoDB no longer relies on THR_LOCK locks so 0 value is returned.
@@ -18933,7 +18932,6 @@ ha_innobase::lock_count(void) const
 {
 	return 0;
 }
-#endif
 
 /*****************************************************************//**
 Supposed to convert a MySQL table lock stored in the 'lock' field of the
@@ -19181,8 +19179,6 @@ ha_innobase::store_lock(
 		lock.type = lock_type;
 	}
 
-	*to++= &lock;
-
 	if (!trx_is_started(trx)
 	    && (m_prebuilt->select_lock_type != LOCK_NONE
 	        || m_prebuilt->stored_select_lock_type != LOCK_NONE)) {
diff --git a/storage/innobase/handler/ha_innodb.h b/storage/innobase/handler/ha_innodb.h
index b436453e610..84feea119c1 100644
--- a/storage/innobase/handler/ha_innodb.h
+++ b/storage/innobase/handler/ha_innodb.h
@@ -274,7 +274,7 @@ public:
 
 	void free_foreign_key_create_info(char* str);
 
-	//uint lock_count(void) const;
+	uint lock_count(void) const;
 
 	THR_LOCK_DATA** store_lock(
 		THD*			thd,
diff --git a/storage/tokudb/mysql-test/tokudb/r/nested_txn_implicit_commit.result b/storage/tokudb/mysql-test/tokudb/r/nested_txn_implicit_commit.result
index ac1a13d5523..f1ea7e20147 100644
--- a/storage/tokudb/mysql-test/tokudb/r/nested_txn_implicit_commit.result
+++ b/storage/tokudb/mysql-test/tokudb/r/nested_txn_implicit_commit.result
@@ -46,7 +46,6 @@ a	b
 1	10
 2	20
 3	30
-4	40
 insert into t2 values (1);
 ERROR HY000: Table 't2' was not locked with LOCK TABLES
 commit;
@@ -59,7 +58,6 @@ a	b
 1	10
 2	20
 3	30
-4	40
 select * from t2;
 a
 1
@@ -72,7 +70,6 @@ a	b
 1	10
 2	20
 3	30
-4	40
 5	50
 select * from t2;
 a
@@ -84,7 +81,6 @@ a	b
 1	10
 2	20
 3	30
-4	40
 5	50
 select * from t2;
 a
diff --git a/storage/tokudb/mysql-test/tokudb_bugs/r/db806.result b/storage/tokudb/mysql-test/tokudb_bugs/r/db806.result
index ae87dbab281..8578bb3b36c 100644
--- a/storage/tokudb/mysql-test/tokudb_bugs/r/db806.result
+++ b/storage/tokudb/mysql-test/tokudb_bugs/r/db806.result
@@ -2,8 +2,8 @@ drop table if exists t1,t3;
 CREATE TABLE t3(a int,c int,d int)engine=TOKUDB;
 lock table t3 read;
 create temporary table t1 engine=tokudb as SELECT 1;
+unlock tables;
 select * from t1;
 1
 1
-unlock tables;
 drop table t1,t3;
diff --git a/storage/tokudb/mysql-test/tokudb_bugs/t/db806.test b/storage/tokudb/mysql-test/tokudb_bugs/t/db806.test
index 3815e59f78c..8dcebe1bb6b 100644
--- a/storage/tokudb/mysql-test/tokudb_bugs/t/db806.test
+++ b/storage/tokudb/mysql-test/tokudb_bugs/t/db806.test
@@ -7,7 +7,7 @@ enable_warnings;
 CREATE TABLE t3(a int,c int,d int)engine=TOKUDB;
 lock table t3 read;
 create temporary table t1 engine=tokudb as SELECT 1;
-select * from t1;
 unlock tables;
+select * from t1;
 
-drop table t1,t3;
\ No newline at end of file
+drop table t1,t3;
diff --git a/storage/xtradb/handler/ha_innodb.cc b/storage/xtradb/handler/ha_innodb.cc
index aa54a5aff5d..0667db03b76 100644
--- a/storage/xtradb/handler/ha_innodb.cc
+++ b/storage/xtradb/handler/ha_innodb.cc
@@ -16125,25 +16125,45 @@ free_share(
 	mysql_mutex_unlock(&innobase_share_mutex);
 }
 
+/*********************************************************************//**
+Returns number of THR_LOCK locks used for one instance of InnoDB table.
+InnoDB no longer relies on THR_LOCK locks so 0 value is returned.
+Instead of THR_LOCK locks InnoDB relies on combination of metadata locks
+(e.g. for LOCK TABLES and DDL) and its own locking subsystem.
+Note that even though this method returns 0, SQL-layer still calls
+::store_lock(), ::start_stmt() and ::external_lock() methods for InnoDB
+tables. */
+
+uint
+ha_innobase::lock_count(void) const
+/*===============================*/
+{
+	return 0;
+}
+
 /*****************************************************************//**
-Converts a MySQL table lock stored in the 'lock' field of the handle to
-a proper type before storing pointer to the lock into an array of pointers.
+Supposed to convert a MySQL table lock stored in the 'lock' field of the
+handle to a proper type before storing pointer to the lock into an array
+of pointers.
+In practice, since InnoDB no longer relies on THR_LOCK locks and its
+lock_count() method returns 0 it just informs storage engine about type
+of THR_LOCK which SQL-layer would have acquired for this specific statement
+on this specific table.
 MySQL also calls this if it wants to reset some table locks to a not-locked
 state during the processing of an SQL query. An example is that during a
 SELECT the read lock is released early on the 'const' tables where we only
 fetch one row. MySQL does not call this when it releases all locks at the
 end of an SQL statement.
-@return	pointer to the next element in the 'to' array */
+@return pointer to the current element in the 'to' array. */
 UNIV_INTERN
 THR_LOCK_DATA**
 ha_innobase::store_lock(
 /*====================*/
 	THD*			thd,		/*!< in: user thread handle */
-	THR_LOCK_DATA**		to,		/*!< in: pointer to an array
-						of pointers to lock structs;
-						pointer to the 'lock' field
-						of current handle is stored
-						next to this array */
+	THR_LOCK_DATA**		to,		/*!< in: pointer to the current
+						element in an array of pointers
+						to lock structs;
+						only used as return value */
 	enum thr_lock_type	lock_type)	/*!< in: lock type to store in
 						'lock'; this may also be
 						TL_IGNORE */
@@ -16362,8 +16382,6 @@ ha_innobase::store_lock(
 		lock.type = lock_type;
 	}
 
-	*to++= &lock;
-
 	if (!trx_is_started(trx)
 	    && (prebuilt->select_lock_type != LOCK_NONE
 	        || prebuilt->stored_select_lock_type != LOCK_NONE)) {
diff --git a/storage/xtradb/handler/ha_innodb.h b/storage/xtradb/handler/ha_innodb.h
index 7b0d20aec72..a79c9e44f25 100644
--- a/storage/xtradb/handler/ha_innodb.h
+++ b/storage/xtradb/handler/ha_innodb.h
@@ -218,6 +218,7 @@ class ha_innobase: public handler
 	bool can_switch_engines();
 	uint referenced_by_foreign_key();
 	void free_foreign_key_create_info(char* str);
+	uint lock_count(void) const;
 	THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
 					enum thr_lock_type lock_type);
 	void init_table_handle_for_HANDLER();