Refactor the innodb_bug38231 mysql-test to conform with the

newly introduced metadata locks.

Previously the behavior was deterministic and if several LOCKs were
waiting the first one of them was released by UNLOCK (in chronological
order).

Now (with MDLs) the behavior is undefined and since we do not know in
what order to --reap the connections we simply disconnect them without
reaping.

mysql-test/suite/innodb/r/innodb_bug38231.result

@@ -1,11 +1,11 @@
 SET storage_engine=InnoDB;
-INSERT INTO bug38231 VALUES (1), (10), (300);
+INSERT INTO bug38231_2 VALUES (1), (10), (300);
 SET autocommit=0;
-SELECT * FROM bug38231 FOR UPDATE;
+SELECT * FROM bug38231_2 FOR UPDATE;
 a
 1
 10
 300
-TRUNCATE TABLE bug38231;
+TRUNCATE TABLE bug38231_2;
 COMMIT;
-DROP TABLE bug38231;
+DROP TABLE bug38231_2;

mysql-test/suite/innodb/t/innodb_bug38231.test

@@ -11,96 +11,79 @@ SET storage_engine=InnoDB;
 -- disable_query_log
 -- disable_result_log
 
-DROP TABLE IF EXISTS bug38231;
+DROP TABLE IF EXISTS bug38231_1;
-CREATE TABLE bug38231 (a INT);
+CREATE TABLE bug38231_1 (a INT);
 
--- connect (con1,localhost,root,,)
+-- connect (lock_gain,localhost,root,,)
--- connect (con2,localhost,root,,)
+-- connect (lock_wait1,localhost,root,,)
--- connect (con3,localhost,root,,)
+-- connect (lock_wait2,localhost,root,,)
+-- connect (truncate_wait,localhost,root,,)
 
--- connection con1
+-- connection lock_gain
 SET autocommit=0;
-LOCK TABLE bug38231 WRITE;
+LOCK TABLE bug38231_1 WRITE;
 
--- connection con2
+-- connection lock_wait1
 SET autocommit=0;
 -- send
-LOCK TABLE bug38231 WRITE;
+LOCK TABLE bug38231_1 WRITE;
 
-# When con1 does UNLOCK below this will release either con2 or con3 which are
+-- connection lock_wait2
-# both waiting on LOCK. At the end we must first --reap and UNLOCK the
-# connection that has been released, otherwise it will wait forever. We assume
-# that the released connection will be the first one that has gained the LOCK,
-# thus we force the order here - con2 does LOCK first, then con3. In other
-# words we wait for LOCK from con2 above to be executed before doing LOCK in
-# con3.
--- connection con1
-let $wait_condition =
-  SELECT COUNT(*) = 1 FROM information_schema.processlist
-  WHERE info = 'LOCK TABLE bug38231 WRITE';
--- source include/wait_condition.inc
-# the above enables query log, re-disable it
--- disable_query_log
-
--- connection con3
 SET autocommit=0;
 -- send
-LOCK TABLE bug38231 WRITE;
+LOCK TABLE bug38231_1 WRITE;
 
--- connection default
+-- connection truncate_wait
 -- send
-TRUNCATE TABLE bug38231;
+TRUNCATE TABLE bug38231_1;
-
--- connection con1
-# Wait for TRUNCATE and the other two LOCKs to be executed; without this,
-# sometimes UNLOCK executes before them. We assume there are no other
-# sessions executing at the same time with the same SQL commands.
-let $wait_condition =
-  SELECT COUNT(*) = 1 FROM information_schema.processlist
-  WHERE info = 'TRUNCATE TABLE bug38231';
--- source include/wait_condition.inc
-let $wait_condition =
-  SELECT COUNT(*) = 2 FROM information_schema.processlist
-  WHERE info = 'LOCK TABLE bug38231 WRITE';
--- source include/wait_condition.inc
-# the above enables query log, re-disable it
--- disable_query_log
 
+-- connection lock_gain
 # this crashes the server if the bug is present
 UNLOCK TABLES;
 
 # clean up
 
--- connection con2
+# do not clean up - we do not know which of the tree has been released
--- reap
+# so the --reap command may hang because the executing command is still
-UNLOCK TABLES;
+# running/waiting
-
+#-- connection lock_wait1
--- connection con3
+#-- reap
--- reap
+#UNLOCK TABLES;
-UNLOCK TABLES;
+#
+#-- connection lock_wait2
+#-- reap
+#UNLOCK TABLES;
+#
+#-- connection truncate_wait
+#-- reap
 
 -- connection default
--- reap
 
--- disconnect con1
+-- disconnect lock_gain
--- disconnect con2
+-- disconnect lock_wait1
--- disconnect con3
+-- disconnect lock_wait2
+-- disconnect truncate_wait
 
-# test that TRUNCATE works with with row-level locks
+DROP TABLE bug38231_1;
+
+# test that TRUNCATE works with row-level locks
+
+DROP TABLE IF EXISTS bug38231_2;
+CREATE TABLE bug38231_2 (a INT);
 
 -- enable_query_log
 -- enable_result_log
 
-INSERT INTO bug38231 VALUES (1), (10), (300);
+INSERT INTO bug38231_2 VALUES (1), (10), (300);
 
 -- connect (con4,localhost,root,,)
 
 -- connection con4
 SET autocommit=0;
-SELECT * FROM bug38231 FOR UPDATE;
+SELECT * FROM bug38231_2 FOR UPDATE;
 
 -- connection default
-TRUNCATE TABLE bug38231;
+TRUNCATE TABLE bug38231_2;
 
 -- connection con4
 COMMIT;
@@ -109,4 +92,4 @@ COMMIT;
 
 -- disconnect con4
 
-DROP TABLE bug38231;
+DROP TABLE bug38231_2;