MDEV-10715 Galera: Replicate MariaDB GTID to other nodes in the cluster

Problem:- Gtid are not transferred in Galera Cluster.

Solution:- We need to transfer gtid in the case on either when cluster is
slave/master in async replication. In normal Gtid replication gtid are generated on
recieving node itself and it is always on sync with other nodes. Because galera keeps
node in sync , So all nodes get same no of event groups. So the issue arises when
say galera is slave in async replication.
A
|    (Async replication)
D <-> E <-> F  {Galera replication}
So what should happen is that all node should apply the master gtid but this does
node happen, becuase node E, F does not recieve gtid from D in write set , So what E(or F)
does is that it applies wsrep_gtid_domain_id, D server-id , E gtid next seq no. This
generated gtid does not always work when say A has different domain id.

So In this commit, on galera node when we see that this event is recieved from master
we simply write Gtid_Log_Event in write_set and send it to other nodes.

1 files changed, 10 insertions, 0 deletions

diff --git a/sql/wsrep_mysqld.cc b/sql/wsrep_mysqld.cc
index bdc8491080d..285bb520b87 100644
--- a/sql/wsrep_mysqld.cc
+++ b/sql/wsrep_mysqld.cc
@@ -1227,6 +1227,16 @@ int wsrep_to_buf_helper(
       if (!ret && writer.write(&gtid_ev)) ret= 1;
   }
 #endif /* GTID_SUPPORT */
+  if (wsrep_gtid_mode && thd->variables.gtid_seq_no)
+  {
+    Gtid_log_event gtid_event(thd, thd->variables.gtid_seq_no,
+                          thd->variables.gtid_domain_id,
+                          true, LOG_EVENT_SUPPRESS_USE_F,
+                          true, 0);
+    gtid_event.server_id= thd->variables.server_id;
+    if (!gtid_event.is_valid()) ret= 0;
+    ret= writer.write(&gtid_event);
+  }
 
   /* if there is prepare query, add event for it */
   if (!ret && thd->wsrep_TOI_pre_query)