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

            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.

1 files changed, 17 insertions, 10 deletions

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