On Wed, Jul 13, 2011 at 10:56 PM, Peter Geoghegan <pe...@2ndquadrant.com> wrote: > Attached is patch for the WAL writer that removes its tight polling > loop (which probably doesn't get hit often in practice, as we just > sleep if wal_writer_delay is under a second), and, at least > potentially, reduces power consumption when idle by using a latch. > > I will break all remaining power consumption work down into > per-auxiliary process patches. I think that this is appropriate - if > we hit a snag on one of the processes, there is no need to have that > hold up everything. > > I've commented that we handle all expected signals, and therefore we > shouldn't worry about having timeout invalidated by signals, just as > with the archiver. Previously, we didn't even worry about Postmaster > death within the tight polling loop, presumably because > wal_writer_delay is typically small enough to avoid that being a > problem. I thought that WL_POSTMASTER_DEATH might be superfluous here, > but then again there is a codepath specifically for the case where > wal_writer_delay exceeds one second, so it is included in this initial > version. > > Comments?
ISTM that this in itself isn't enough to reduce power consumption. Currently the only people that use WALWriter are asynchronous commits, so we should include within RecordTransactionCommit() a SetLatch() command for the WALWriter. That way we can have WALWriter sleep until its needed. -- Simon Riggs 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
