Bug #21494 Master Cluster MySQLD is point of failure that can lead to mismatch slave data

- insert gap event on cluster connect

sql/ha_ndbcluster_binlog.cc

@@ -3589,6 +3589,14 @@ pthread_handler_t ndb_binlog_thread_func(void *arg)
   /*
     Main NDB Injector loop
   */
+  {
+    /*
+      Always insert a GAP event as we cannot know what has happened in the cluster
+      while not being connected.
+    */
+    LEX_STRING const msg= { C_STRING_WITH_LEN("Cluster connect") };
+    inj->record_incident(thd, INCIDENT_LOST_EVENTS, msg);
+  }
   {
     thd->proc_info= "Waiting for ndbcluster to start";
 

sql/rpl_injector.cc

@@ -198,7 +198,7 @@ int injector::record_incident(THD *thd, Incident incident)
   return 0;
 }
 
-int injector::record_incident(THD *thd, Incident incident, LEX_STRING message)
+int injector::record_incident(THD *thd, Incident incident, LEX_STRING const message)
 {
   Incident_log_event ev(thd, incident, message);
   if (int error= mysql_bin_log.write(&ev))

sql/rpl_injector.h

@@ -324,7 +324,7 @@ class injector
     void        new_trans(THD *, transaction *);
 
     int record_incident(THD*, Incident incident);
-    int record_incident(THD*, Incident incident, LEX_STRING message);
+    int record_incident(THD*, Incident incident, LEX_STRING const message);
 
 private:
     explicit injector();