On Wed, Dec 11, 2013 at 1:28 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > But nobody has given a sensible answer to my questions, other than to > roll out the same general points again. In practice, its a knob that > does not do very much of use for us. At best it is addressing the > symptoms, not the cause. IMHO.
It's just a usability feature. It lessens the intellectual overhead of managing maintenance_work_mem. I understand that it isn't very impressive from a technical point of view. However, in many environments, it actually will make a significant difference, because non-autovacuum maintenance operations are very rare compared to autovacuum workers vacuuming, and therefore I can now afford to be much less conservative in setting maintenance_work_mem globally on each of 8 Postgres instances hosted on a single box. These are precisely the kinds of Postgres instances where users are very unlikely to have heard of maintenance_work_mem at all. These users are not even using an admin tool in many cases, preferring to rely on ORM migrations. Having said that, it's also something I'll find useful on a day to day basis, because it's a chore to set maintenace_work_mem manually, and sometimes I forget to do so, particularly when under pressure to relieve a production performance issues on a random customer's database. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
