Peter Eisentraut <peter.eisentr...@2ndquadrant.com> writes: > The reason for this confusion is that synchronous_commit has both a > local and a remote meaning, and in this case the local meaning on the > subscriber has an impact on the remote meaning of the publisher.
And another, if I get it right, is that while asynchronous commit makes server report 'success' faster, it also makes the actual WAL writing to the disk *slower* in terms of latency, because this action is delayed for some arbitrary time (well, to be exactly, up to 3*wal_writer_delay milliseconds). As for synchronous commit, its WAL is written as soon as possible, though I am not sure which guarantees exist here -- walwriter is woken up each wal_writer_delay ms, but it seems to write only fully completed pages under heavy load. Please correct me if I am wrong. In general, it's clear now, thanks. -- Arseny Sher -- Sent via pgsql-docs mailing list (pgsql-docs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-docs
