merge

mysql-test/r/delayed.result

@@ -310,4 +310,16 @@ a	b
 2	2
 drop table t1;
 set global low_priority_updates = @old_delayed_updates;
+#
+# Bug #47682 strange behaviour of INSERT DELAYED
+#
+DROP TABLE IF EXISTS t1, t2;
+CREATE TABLE t1 (f1 integer);
+CREATE TABLE t2 (f1 integer);
+FLUSH TABLES WITH READ LOCK;
+LOCK TABLES t1 READ;
+INSERT DELAYED INTO t2 VALUES (1);
+ERROR HY000: Can't execute the query because you have a conflicting read lock
+UNLOCK TABLES;
+DROP TABLE t1, t2;
 End of 5.1 tests

mysql-test/t/delayed.test

@@ -328,4 +328,26 @@ drop table t1;
 
 set global low_priority_updates = @old_delayed_updates;
 
+
+--echo #
+--echo # Bug #47682 strange behaviour of INSERT DELAYED
+--echo #
+
+--disable_warnings
+DROP TABLE IF EXISTS t1, t2;
+--enable_warnings
+
+CREATE TABLE t1 (f1 integer);
+CREATE TABLE t2 (f1 integer);
+
+FLUSH TABLES WITH READ LOCK;
+LOCK TABLES t1 READ;
+
+--error ER_CANT_UPDATE_WITH_READLOCK
+INSERT DELAYED INTO t2 VALUES (1);
+
+UNLOCK TABLES;
+DROP TABLE t1, t2;
+
+
 --echo End of 5.1 tests

sql/sql_insert.cc

@@ -500,6 +500,22 @@ bool open_and_lock_for_insert_delayed(THD *thd, TABLE_LIST *table_list)
   DBUG_ENTER("open_and_lock_for_insert_delayed");
 
 #ifndef EMBEDDED_LIBRARY
+  if (thd->locked_tables && thd->global_read_lock)
+  {
+    /*
+      If this connection has the global read lock, the handler thread
+      will not be able to lock the table. It will wait for the global
+      read lock to go away, but this will never happen since the
+      connection thread will be stuck waiting for the handler thread
+      to open and lock the table.
+      If we are not in locked tables mode, INSERT will seek protection
+      against the global read lock (and fail), thus we will only get
+      to this point in locked tables mode.
+    */
+    my_error(ER_CANT_UPDATE_WITH_READLOCK, MYF(0));
+    DBUG_RETURN(TRUE);
+  }
+
   if (delayed_get_table(thd, table_list))
     DBUG_RETURN(TRUE);