Hi, For reliable high-availability, when the master crashes, the clusterware must know whether it can promote the standby safely without any data loss, before actually promoting it. IOW, it must know whether the standby has already caught up with the primary. Otherwise, failover might cause data loss. We can know that from pg_stat_replication on the master. But the problem is that pg_stat_replication is not available since the master is not running at that moment. So that info should be available also on the standby.
To achieve that, I'm thinking to change walsender so that, when the standby has caught up with the master, it sends back the message indicating that to the standby. And I'm thinking to add new function (or view like pg_stat_replication) available on the standby, which shows that info. Thought? Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
