Hi, In the case where there are multiple standbys, when a failover happens, we usually calculate most advanced standby by using pg_last_xlog_receive_location or pg_last_xlog_replay_location, and promote it to new master. The problem is that neither function might return the right last location of WAL available in the standby. So we cannot use them to check which standby is most ahead.
Since pg_last_xlog_receive_location moves backwards when the standby attempts to reconnect to the primary, it might fall behind the last location of WAL available. OTOH, pg_last_xlog_replay_location might also fall behind because of Hot Standby query conflict. So I'm thinking to change pg_last_xlog_receive_location not to move backwards. There is no need to move it backwards when the standby reconnects to the primary. So we can do that. BTW, the related discussion was done before: http://archives.postgresql.org/pgsql-hackers/2010-06/msg00576.php 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
