Heikki Linnakangas wrote: > Tom Lane wrote: > > I've committed the HOT patch. > > Thanks, much easier to work with it now that it's in. > > > I'd still like to think about whether we > > can be smarter about when to invoke pruning, but that's a small enough > > issue that the patch can go in without it. > > Yeah. I'm doing some micro-benchmarking, and the attached test case is > much slower with HOT. It's spending a lot of time trying to prune, only > to find out that it can't. > > Instead of/in addition to avoiding pruning when it doesn't help, maybe > we could make HeapTupleSatisfiesVacuum cheaper. > > I'm going to continue testing, this is just a heads-up that HOT as > committed seriously hurts performance in some cases. (though one can > argue that this test case isn't a very realistic one.)
This might be a simplistic question but if the page is +90% full and there is a long-lived transaction, isn't Postgres going to try pruning on each page read access? -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
