1 files changed, 13 insertions, 1 deletions
diff --git a/sql/sql_class.h b/sql/sql_class.h
index a2c622b2326..8a427057d83 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -2795,7 +2795,19 @@ public:
   {
     DBUG_ASSERT(locked_tables_mode == LTM_NONE);
 
-    mdl_context.set_explicit_duration_for_all_locks();
+    if (mode_arg == LTM_LOCK_TABLES)
+    {
+      /*
+        When entering LOCK TABLES mode we should set explicit duration
+        for all metadata locks acquired so far in order to avoid releasing
+        them till UNLOCK TABLES statement.
+        We don't do this when entering prelocked mode since sub-statements
+        don't release metadata locks and restoring status-quo after leaving
+        prelocking mode gets complicated.
+      */
+      mdl_context.set_explicit_duration_for_all_locks();
+    }
+
     locked_tables_mode= mode_arg;
   }
   void leave_locked_tables_mode();