Merge next-4248 -> next-4284-merge

mysql-test/r/mdl_sync.result

@@ -2244,3 +2244,51 @@ FLUSH TABLES WITH READ LOCK;
 UNLOCK TABLES;
 # Connection 1
 SET DEBUG_SYNC= 'RESET';
+#
+# Bug#50786 Assertion `thd->mdl_context.trans_sentinel() == __null' 
+#           failed in open_ltable()
+#
+DROP TABLE IF EXISTS t1, t2;
+CREATE TABLE t1 (i INT);
+CREATE TABLE t2 (i INT);
+SET @old_general_log= @@global.general_log;
+SET @@global.general_log= 1;
+SET @old_log_output= @@global.log_output;
+SET @@global.log_output= 'TABLE';
+SET @old_sql_log_off= @@session.sql_log_off;
+SET @@session.sql_log_off= 1;
+# connection: con1
+HANDLER t1 OPEN;
+# connection: con3
+SET @@session.sql_log_off= 1;
+# connection: con2
+SET DEBUG_SYNC= 'thr_multi_lock_after_thr_lock SIGNAL parked WAIT_FOR go';
+# Sending:
+SELECT 1;
+# connection: con3
+SET DEBUG_SYNC= 'now WAIT_FOR parked';
+# connection: con1
+# Sending:
+SELECT 1;
+# connection: con3
+# Sending:
+ALTER TABLE t1 ADD COLUMN j INT;
+# connection: default
+SET DEBUG_SYNC= 'now SIGNAL go';
+# connection: con1
+# Reaping SELECT 1
+1
+1
+HANDLER t1 CLOSE;
+# connection: con2
+# Reaping SELECT 1
+1
+1
+# connection: con3
+# Reaping ALTER TABLE t1 ADD COLUMN j INT
+# connection: default
+DROP TABLE t1, t2;
+SET DEBUG_SYNC= 'RESET';
+SET @@global.general_log= @old_general_log;
+SET @@global.log_output= @old_log_output;
+SET @@session.sql_log_off= @old_sql_log_off;

mysql-test/t/mdl_sync.test

@@ -3212,6 +3212,109 @@ SET DEBUG_SYNC= 'RESET';
 disconnect con2;
 
 
+--echo #
+--echo # Bug#50786 Assertion `thd->mdl_context.trans_sentinel() == __null' 
+--echo #           failed in open_ltable()
+--echo #
+
+--disable_warnings
+DROP TABLE IF EXISTS t1, t2;
+--enable_warnings
+
+connect (con1,localhost,root);
+connect (con2,localhost,root);
+connect (con3,localhost,root);
+connection default;
+
+CREATE TABLE t1 (i INT);
+CREATE TABLE t2 (i INT);
+
+SET @old_general_log= @@global.general_log;
+SET @@global.general_log= 1;
+
+SET @old_log_output= @@global.log_output;
+SET @@global.log_output= 'TABLE';
+
+SET @old_sql_log_off= @@session.sql_log_off;
+SET @@session.sql_log_off= 1;
+
+--echo # connection: con1
+connection con1;
+HANDLER t1 OPEN;
+
+--echo # connection: con3
+connection con3;
+SET @@session.sql_log_off= 1;
+
+--echo # connection: con2
+connection con2;
+SET DEBUG_SYNC= 'thr_multi_lock_after_thr_lock SIGNAL parked WAIT_FOR go';
+
+# The below statement will block on the debug sync point
+# after it gets write lock on mysql.general_log table.
+--echo # Sending:
+--send SELECT 1
+
+--echo # connection: con3
+connection con3;
+SET DEBUG_SYNC= 'now WAIT_FOR parked';
+
+--echo # connection: con1
+connection con1;
+# This statement will block in open_ltable() when
+# trying to write into mysql.general_log.
+--echo # Sending:
+--send SELECT 1
+
+--echo # connection: con3
+connection con3;
+let $wait_condition=
+  SELECT COUNT(*) = 1 FROM information_schema.processlist
+  WHERE state = "Table lock" and info = "SELECT 1";
+--source include/wait_condition.inc
+# The ALTER below will try to abort the statement in connection con1,
+# since the latter waits on a table-level lock while having a HANDLER
+# open. This will cause mysql_lock_tables() in con1 fail which before
+# triggered the assert.
+--echo # Sending:
+--send ALTER TABLE t1 ADD COLUMN j INT
+
+--echo # connection: default
+connection default;
+let $wait_condition=
+  SELECT COUNT(*) = 1 FROM information_schema.processlist
+  WHERE state = "Waiting for table" 
+  AND info = "ALTER TABLE t1 ADD COLUMN j INT";
+--source include/wait_condition.inc
+SET DEBUG_SYNC= 'now SIGNAL go';
+
+--echo # connection: con1
+connection con1;
+--echo # Reaping SELECT 1
+--reap
+HANDLER t1 CLOSE;
+
+--echo # connection: con2
+connection con2;
+--echo # Reaping SELECT 1
+--reap
+
+--echo # connection: con3
+connection con3;
+--echo # Reaping ALTER TABLE t1 ADD COLUMN j INT
+--reap
+
+--echo # connection: default
+connection default;
+DROP TABLE t1, t2;
+SET DEBUG_SYNC= 'RESET';
+disconnect con1;
+disconnect con2;
+disconnect con3;
+SET @@global.general_log= @old_general_log;
+SET @@global.log_output= @old_log_output;
+SET @@session.sql_log_off= @old_sql_log_off;
+
 # Check that all connections opened by test cases in this file are really
 # gone so execution of other tests won't be affected by their presence.
 --source include/wait_until_count_sessions.inc

sql/mdl.h

@@ -540,7 +540,7 @@ class MDL_context
             always re-try reading it after small timeout and therefore
             will see the new value eventually.
     */
-    m_needs_thr_lock_abort= TRUE;
+    m_needs_thr_lock_abort= needs_thr_lock_abort;
   }
   bool get_needs_thr_lock_abort() const
   {

sql/sql_base.cc

@@ -4996,8 +4996,6 @@ TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type lock_type,
   while ((error= open_table(thd, table_list, thd->mem_root, &ot_ctx, 0)) &&
          ot_ctx.can_recover_from_failed_open())
   {
-    /* We never have an open HANDLER, LOCK TABLES or GRL here. */
-    DBUG_ASSERT(thd->mdl_context.trans_sentinel() == NULL);
     /*
       Even though we have failed to open table we still need to
       call release_transactional_locks() to release metadata locks which
@@ -5048,8 +5046,6 @@ TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type lock_type,
             close_thread_tables(thd);
             table_list->table= NULL;
             table_list->mdl_request.ticket= NULL;
-            /* We never have an open HANDLER, LOCK TABLES or GRL here. */
-            DBUG_ASSERT(thd->mdl_context.trans_sentinel() == NULL);
             thd->mdl_context.rollback_to_savepoint(ot_ctx.start_of_statement_svp());
             goto retry;
           }