Re: Uh, I change my mind about commit_delay + commit_siblings (sort of)
Peter Geoghegan <peter@2ndquadrant.com>
From: Peter Geoghegan <peter@2ndquadrant.com>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, Simon Riggs <simon@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org, tgl@sss.pgh.pa.us
Date: 2012-06-28T18:38:35Z
Lists: pgsql-hackers
On 28 June 2012 19:25, Kevin Grittner <Kevin.Grittner@wicourts.gov> wrote: > Peter Geoghegan <peter@2ndquadrant.com> wrote: > >> Is anyone aware of a non-zero commit_delay in the wild today? I >> personally am not. > > http://archives.postgresql.org/pgsql-performance/2011-11/msg00083.php In that thread, Robert goes on to say to the OP that has set commit_delay: >On Fri, Nov 4, 2011 at 2:45 PM, Claudio Freire <klaussfreire@gmail.com> wrote: >> I don't think 1 second can be such a big difference for the bgwriter, >> but I might be wrong. > > Well, the default value is 200 ms. And I've never before heard of > anyone tuning it up, except maybe to save on power consumption on a > system with very low utilization. Nearly always you want to reduce > it. > >> The wal_writer makes me doubt, though. If logged activity was higher >> than 8MB/s, then that setting would block it all. >> I guess I really should lower it. > > Here again, you've set it to ten times the default value. That > doesn't seem like a good idea. I would start with the default and > tune down. So, let me rephrase my question: Is anyone aware of a non-zero commit_delay in the wild today with sensible reasoning behind it? -- Peter Geoghegan http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training and Services