MW-258 - RSU DDL should not rely on the global wsrep_desync variable value and...

MW-258 - RSU DDL should not rely on the global wsrep_desync variable value and should always try to desync on its own.

mysql-test/suite/galera/r/MW-258.result

+CREATE TABLE t1 (f1 INTEGER);
+LOCK TABLE t1 WRITE;
+value prior to RSU:
+SHOW STATUS LIKE 'wsrep_desync_count';
+Variable_name	Value
+wsrep_desync_count	0
+SHOW VARIABLES LIKE 'wsrep_desync';
+Variable_name	Value
+wsrep_desync	OFF
+SET SESSION wsrep_sync_wait = 0;
+SET SESSION wsrep_osu_method = RSU;
+ALTER TABLE t1 ADD COLUMN f2 INTEGER;;
+SET SESSION wsrep_sync_wait = 0;
+SET SESSION wsrep_osu_method = RSU;
+ALTER TABLE t1 ADD COLUMN f3 INTEGER;;
+value during RSU:
+SHOW STATUS LIKE 'wsrep_desync_count';
+Variable_name	Value
+wsrep_desync_count	2
+SHOW VARIABLES LIKE 'wsrep_desync';
+Variable_name	Value
+wsrep_desync	OFF
+SHOW PROCESSLIST;
+Id	User	Host	db	Command	Time	State	Info	Progress
+#	system user	#	NULL	Sleep	#	NULL	NULL	0.000
+#	system user	#	NULL	Sleep	#	wsrep aborter idle	NULL	0.000
+#	root	#	test	Sleep	#		NULL	0.000
+#	root	#	test	Query	#	init	SHOW PROCESSLIST	0.000
+#	root	#	test	Query	#	Waiting for table metadata lock	ALTER TABLE t1 ADD COLUMN f2 INTEGER	0.000
+#	root	#	test	Query	#	checking permissions	ALTER TABLE t1 ADD COLUMN f3 INTEGER	0.000
+UNLOCK TABLES;
+value after RSU:
+SHOW STATUS LIKE 'wsrep_desync_count';
+Variable_name	Value
+wsrep_desync_count	0
+SHOW VARIABLES LIKE 'wsrep_desync';
+Variable_name	Value
+wsrep_desync	OFF
+SET GLOBAL wsrep_desync=0;
+Warnings:
+Warning	1231	'wsrep_desync' is already OFF.
+DROP TABLE t1;

mysql-test/suite/galera/t/MW-258.test

+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+
+--connection node_1
+CREATE TABLE t1 (f1 INTEGER);
+LOCK TABLE t1 WRITE;
+--echo value prior to RSU:
+SHOW STATUS LIKE 'wsrep_desync_count';
+SHOW VARIABLES LIKE 'wsrep_desync';
+
+--connect node_1a, 127.0.0.1, root, , test, $NODE_MYPORT_1
+--connection node_1a
+SET SESSION wsrep_sync_wait = 0;
+SET SESSION wsrep_osu_method = RSU;
+--send ALTER TABLE t1 ADD COLUMN f2 INTEGER;
+
+--connect node_1b, 127.0.0.1, root, , test, $NODE_MYPORT_1
+--connection node_1b
+SET SESSION wsrep_sync_wait = 0;
+SET SESSION wsrep_osu_method = RSU;
+--send ALTER TABLE t1 ADD COLUMN f3 INTEGER;
+
+--sleep 5
+--connection node_1
+--echo value during RSU:
+SHOW STATUS LIKE 'wsrep_desync_count';
+SHOW VARIABLES LIKE 'wsrep_desync';
+--replace_column 1 # 3 # 6 #
+SHOW PROCESSLIST;
+UNLOCK TABLES;
+
+--connection node_1a
+--reap
+--connection node_1b
+--reap
+
+--connection node_1
+--echo value after RSU:
+SHOW STATUS LIKE 'wsrep_desync_count';
+SHOW VARIABLES LIKE 'wsrep_desync';
+SET GLOBAL wsrep_desync=0;
+
+DROP TABLE t1;

sql/wsrep_mysqld.cc

@@ -1308,19 +1308,15 @@ static int wsrep_RSU_begin(THD *thd, char *db_, char *table_)
   WSREP_DEBUG("RSU BEGIN: %lld, %d : %s", (long long)wsrep_thd_trx_seqno(thd),
                thd->wsrep_exec_mode, thd->query() );
 
-  if (!wsrep_desync)
+  ret = wsrep->desync(wsrep);
+  if (ret != WSREP_OK)
   {
-    ret = wsrep->desync(wsrep);
-    if (ret != WSREP_OK)
-    {
-      WSREP_WARN("RSU desync failed %d for schema: %s, query: %s",
-                 ret, (thd->db ? thd->db : "(null)"), thd->query());
-      my_error(ER_LOCK_DEADLOCK, MYF(0));
-      return(ret);
-    }
+    WSREP_WARN("RSU desync failed %d for schema: %s, query: %s",
+               ret, (thd->db ? thd->db : "(null)"), thd->query());
+    my_error(ER_LOCK_DEADLOCK, MYF(0));
+    return(ret);
   }
-  else
-    WSREP_DEBUG("RSU desync skipped: %d", wsrep_desync);
+
   mysql_mutex_lock(&LOCK_wsrep_replaying);
   wsrep_replaying++;
   mysql_mutex_unlock(&LOCK_wsrep_replaying);
@@ -1335,15 +1331,13 @@ static int wsrep_RSU_begin(THD *thd, char *db_, char *table_)
     wsrep_replaying--;
     mysql_mutex_unlock(&LOCK_wsrep_replaying);
 
-    if (!wsrep_desync)
+    ret = wsrep->resync(wsrep);
+    if (ret != WSREP_OK)
     {
-      ret = wsrep->resync(wsrep);
-      if (ret != WSREP_OK)
-      {
-        WSREP_WARN("resync failed %d for schema: %s, query: %s",
-                   ret, (thd->db ? thd->db : "(null)"), thd->query());
-      }
+      WSREP_WARN("resync failed %d for schema: %s, query: %s",
+                 ret, (thd->db ? thd->db : "(null)"), thd->query());
     }
+
     my_error(ER_LOCK_DEADLOCK, MYF(0));
     return(1);
   }
@@ -1379,18 +1373,15 @@ static void wsrep_RSU_end(THD *thd)
                (thd->db ? thd->db : "(null)"),
                thd->query());
   }
-  if (!wsrep_desync)
+
+  ret = wsrep->resync(wsrep);
+  if (ret != WSREP_OK)
   {
-    ret = wsrep->resync(wsrep);
-    if (ret != WSREP_OK)
-    {
-      WSREP_WARN("resync failed %d for schema: %s, query: %s", ret,
-                 (thd->db ? thd->db : "(null)"), thd->query());
-      return;
-    }
+    WSREP_WARN("resync failed %d for schema: %s, query: %s", ret,
+               (thd->db ? thd->db : "(null)"), thd->query());
+    return;
   }
-  else
-    WSREP_DEBUG("RSU resync skipped: %d", wsrep_desync);
+
   thd->variables.wsrep_on = 1;
 }