On Mon, Jun 8, 2015 at 1:23 PM, Alvaro Herrera <alvherre@xxxxxxxxxxxxxxx> wrote: > Andres Freund wrote: >> On June 8, 2015 7:06:31 PM GMT+02:00, Alvaro Herrera <alvherre@xxxxxxxxxxxxxxx> wrote: >> >I might be misreading the code, but PMSIGNAL_START_AUTOVAC_LAUNCHER >> >only causes things to happen (i.e. a new worker to be started) when >> >autovacuum is disabled. If autovacuum is enabled, postmaster >> >receives the signal and doesn't do anything about it, because the >> >launcher is already running. Of course, regularly scheduled autovac >> >workers will eventually start running, but perhaps this is not good >> >enough. >> >> Well that's just the same for the plain xid precedent? I'd not mind >> improving further, but that seems like a separate thing. > > Sure. I just concern that we might be putting excessive trust on > emergency workers being launched at a high pace. With normally > configured systems (naptime=1min) it shouldn't be a problem, but we have > seen systems with naptime set to one hour or so, and those might feel > some pain; and it would get worse the more databases you have, because > people might feel the need to space the autovac runs even more. > > (My personal alarm bells go off when I see autovac_naptime=15min or > more, but apparently not everybody sees things that way.) Uh, I'd echo that sentiment if you did s/15min/1min/ I think Andres's patch is just improving the existing mechanism so that it's reliable, and you're proposing something notably different which might be better, but which is really a different proposal altogether. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
