Refs codership/mysql-wsrep#113 - Extended the protection of local FLUSH

sessions to cover all exclusive MDL locks

Author: sjaakola

sql/mdl.cc

@@ -3373,4 +3373,21 @@ void MDL_ticket::wsrep_report(bool debug)
          psi_stage->m_name);
     }
 }
+bool MDL_context::wsrep_has_explicit_locks()
+{
+  MDL_ticket *ticket = NULL;
+
+  Ticket_iterator it(m_tickets[MDL_EXPLICIT]);
+
+  while ((ticket = it++))
+  {
+    if (ticket->m_type == MDL_EXCLUSIVE)
+    {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 #endif /* WITH_WSREP */

sql/mdl.h

@@ -934,7 +934,8 @@ class MDL_context
 public:
 #ifdef WITH_WSREP
   THD *wsrep_get_thd() const { return get_thd(); }
-#endif
+  bool wsrep_has_explicit_locks();
+#endif /* WITH_WSREP */
   void find_deadlock();
 
   ulong get_thread_id() const { return thd_get_thread_id(get_thd()); }

sql/sql_class.cc

@@ -861,7 +861,6 @@ extern "C" const char *wsrep_thd_exec_mode_str(THD *thd)
   return 
     (!thd) ? "void" :
     (thd->wsrep_exec_mode == LOCAL_STATE)  ? "local"         :
-    (thd->wsrep_exec_mode == LOCAL_FLUSH)  ? "flush"         :
     (thd->wsrep_exec_mode == REPL_RECV)    ? "applier"       :
     (thd->wsrep_exec_mode == TOTAL_ORDER)  ? "total order"   : 
     (thd->wsrep_exec_mode == LOCAL_COMMIT) ? "local commit"  : "void";

sql/sql_parse.cc

@@ -4165,11 +4165,6 @@ case SQLCOM_PREPARE:
   }
 
   case SQLCOM_UNLOCK_TABLES:
-#ifdef WITH_WSREP
-    mysql_mutex_lock(&thd->LOCK_wsrep_thd);
-    if (thd->wsrep_exec_mode == LOCAL_FLUSH) thd->wsrep_exec_mode = LOCAL_STATE;
-    mysql_mutex_unlock(&thd->LOCK_wsrep_thd);
-#endif /* WITH_WSREP */
     /*
       It is critical for mysqldump --single-transaction --master-data that
       UNLOCK TABLES does not implicitely commit a connection which has only
@@ -4672,12 +4667,6 @@ case SQLCOM_PREPARE:
                              FALSE, UINT_MAX, FALSE))
         goto error;
 
-#ifdef WITH_WSREP
-      mysql_mutex_lock(&thd->LOCK_wsrep_thd);
-      thd->wsrep_exec_mode = LOCAL_FLUSH;
-      mysql_mutex_unlock(&thd->LOCK_wsrep_thd);
-#endif /* WITH_WSREP */
-
       if (flush_tables_with_read_lock(thd, all_tables))
         goto error;
 
@@ -4698,12 +4687,6 @@ case SQLCOM_PREPARE:
     {
       WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL)
     }
-    else
-    {
-      mysql_mutex_lock(&thd->LOCK_wsrep_thd);
-      thd->wsrep_exec_mode = LOCAL_FLUSH;
-      mysql_mutex_unlock(&thd->LOCK_wsrep_thd);
-    }
 #endif /* WITH_WSREP*/
 
     /*

sql/wsrep_hton.cc

@@ -40,7 +40,7 @@ void wsrep_cleanup_transaction(THD *thd)
   thd->wsrep_ws_handle.trx_id= WSREP_UNDEFINED_TRX_ID;
   thd->wsrep_trx_meta.gtid= WSREP_GTID_UNDEFINED;
   thd->wsrep_trx_meta.depends_on= WSREP_SEQNO_UNDEFINED;
-  if (thd->wsrep_exec_mode != LOCAL_FLUSH) thd->wsrep_exec_mode= LOCAL_STATE;
+  thd->wsrep_exec_mode= LOCAL_STATE;
   return;
 }
 

sql/wsrep_mysqld.cc

@@ -1500,7 +1500,7 @@ wsrep_grant_mdl_exception(MDL_context *requestor_ctx,
       ret = TRUE;
     }
     else if (granted_thd->lex->sql_command == SQLCOM_FLUSH ||
-             granted_thd->wsrep_exec_mode == LOCAL_FLUSH)
+             granted_thd->mdl_context.wsrep_has_explicit_locks())
     {
       WSREP_DEBUG("BF thread waiting for FLUSH");
       ticket->wsrep_report(wsrep_debug);

sql/wsrep_mysqld.h

@@ -30,8 +30,6 @@ class THD;
 enum wsrep_exec_mode {
   /* Transaction processing before replication. */
   LOCAL_STATE,
-  /* Local flush. */
-  LOCAL_FLUSH,
   /* Slave thread applying write sets from other nodes or replaying thread. */
   REPL_RECV,
   /* Total-order-isolation mode */

sql/wsrep_thd.cc

@@ -611,3 +611,8 @@ int wsrep_thd_in_locking_session(void *thd_ptr)
   return 0;
 }
 
+bool wsrep_thd_has_explicit_locks(THD *thd)
+{
+  assert(thd);
+  return (thd->mdl_context.wsrep_has_explicit_locks());
+}