Jim C. Nasby wrote: > On Thu, Feb 22, 2007 at 10:32:44PM -0500, Matthew T. O'Connor wrote:
> > I'm not sure this is a great idea, but I don't see how this would result > > in large numbers of workers working in one database. If workers work > > on tables in size order, and exit as soon as they catch up to an older > > worker, I don't see the problem. Newer works are going to catch-up to > > older workers pretty quickly since small tables will vacuum fairly quickly. > > The reason that won't necessarily happen is because you can get large > tables popping up as needing vacuuming at any time. Right. We know that a table that needs frequent vacuum necessarily has to be small -- so maybe have the second worker exit when it catches up with the first, or when the next table is above 1 GB, whichever happens first. That way, only the first worker can be processing the huge tables. The problem with this is that if one of your hot tables grows a bit larger than 1 GB, you suddenly have a change in autovacuuming behavior, for no really good reason. And while your second worker is processing the tables in the hundreds-MB range, your high-update 2 MB tables are neglected :-( -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
