On Tue, Jun 7, 2011 at 8:27 AM, Heikki Linnakangas <heikki.linnakan...@enterprisedb.com> wrote: > On 07.06.2011 10:21, Simon Riggs wrote: >> >> On Mon, Jun 6, 2011 at 11:25 PM, Robert Haas<robertmh...@gmail.com> >> wrote: >>> >>> It strikes me, though, that we >>> could probably get nearly all of the benefit of this patch by being >>> willing to zero the first sizeof(XLogRecord) bytes following a record, >>> but not the rest of the buffer. That would pretty much wipe out any >>> chance of an xl_prev match, I think, and would likely still get nearly >>> all of the performance benefit. >> >> Which adds something onto the path of every XlogInsert(), rather than >> once per page, so I'm a little hesitant to agree. > > You would only need to do it just before you write out the WAL. I guess > you'd need to grab WALInsertLock in XLogWrite() to prevent more WAL records > from being inserted on the page until you're done zeroing it, though.
How would that help? -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
