On Wed, Dec 22, 2010 at 11:12 AM, Merlin Moncure <mmonc...@gmail.com> wrote: > On Wed, Dec 22, 2010 at 11:06 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> Merlin Moncure <mmonc...@gmail.com> writes: >>> well, simon's point that hint bits complicate checksum may nor may not >>> be the case, but no hint bits = less i/o = less checksumming (unless >>> you checksum around the hint bits). >> >> I think you're optimistically assuming the extra clog accesses don't >> cost any I/O. > > right, but clog is much more highly packed which is both a good and a > bad thing. my conjecture here is that jamming the clog files is > actually good, because that keeps them 'hot' and more than compensates > the extra heap i/o. the extra lock of course is scary.
er, should have said, plus less heap i/o compensates the extra clog i/o. merlin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
