Merge pull request #12 from satya-bodapati/replace-fix

DISTMYSQL-243 - Orchestrator uses inefficient subquery in REPLACE to …

Author: satya-bodapati

go/inst/cluster_alias_dao.go

@@ -126,16 +126,15 @@ func UpdateClusterAliases() error {
 				    left join database_instance_downtime using (hostname, port)
 				  where
 				    suggested_cluster_alias!=''
+						and cluster_name != ''
 						/* exclude newly demoted, downtimed masters */
 						and ifnull(
 								database_instance_downtime.downtime_active = 1
 								and database_instance_downtime.end_timestamp > now()
 								and database_instance_downtime.reason = ?
 							, 0) = 0
-					order by
-						ifnull(last_checked <= last_seen, 0) asc,
-						read_only desc,
-						num_slave_hosts asc
+					group by
+					       suggested_cluster_alias, cluster_name
 			`, DowntimeLostInRecoveryMessage)
 		return log.Errore(err)
 	}