On Sun, May 29, 2011 at 8:10 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > =?ISO-8859-1?Q?C=E9dric_Villemain?= <cedric.villemain.deb...@gmail.com> > writes: >> 2011/5/29 Tom Lane <t...@sss.pgh.pa.us>: >>> OK, do you like the attached version of that logic? (Other fragments >>> of the patch as before.) > >> The idea was that remove only one page from the VACUUM will prevent >> relfrozenxid update and reltuples (and relpages) update. >> Now, I beleive that once we've skip at least one page thanks to >> SKIP_PAGES_THRESHOLD, then we should be more agressive and remove as >> many as possible pages from the VACUUM, tks to the VM. > > That would require proof, not just suggestion. Skipping pages will > defeat the OS read-ahead algorithm, and so could easily cost more than > reading them. >
My worry is what we have right now is also based on just assumptions and gut feelings rather than any numbers. Thanks, Pavan -- Pavan Deolasee EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
