On 8/30/21, 12:52 PM, "alvhe...@alvh.no-ip.org" <alvhe...@alvh.no-ip.org> wrote: > On 2021-Aug-28, Andres Freund wrote: > >> While rebasing the aio patchset ontop of HEAD I noticed that this commit >> added >> another atomic operation to XLogWrite() with archiving enabled. The WAL write >> path is really quite hot, and at least some of the >> NotifySegmentsReadyForArchive() calls are done while WALWriteLock is held. >> >> I think we should at least try to make the fast-path where no segment >> boundaries were crossed use no atomic operations. > > I think the best way to achieve this is is to rely completely on > walwriter doing the segment notification, so that the WAL write done by > backend would only do a latch set.
+1. If we do that, we may also want to move NotifySegmentsReadyForArchive() to after the call to XLogBackgroundFlush() in the WAL writer. Nathan
