On 2012-11-30 16:09:15 -0500, Tom Lane wrote: > Claudio Freire <klaussfre...@gmail.com> writes: > > Without hot standby feedback, reporting queries are impossible. I've > > experienced it. Cancellations make it impossible to finish any > > decently complex reporting query. > > The original expectation was that slave-side cancels would be > infrequent. Maybe there's some fixing/tuning to be done there.
I've mostly seen snapshot conflicts. Its hard to say anything more precise because we don't log any additional information (its admittedly not easy). I think it would already help a lot if ResolveRecoveryConflictWithSnapshot would log: * the relfilenode (already passed) * the removed xid * the pid of the backend holding the oldest snapshot * the oldest xid of that backend Most of that should be easy to get. But I don't think we really can expect a very low rate of conflicts if the primary has few longrunning transactions but the standby does. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
