On Tue, Jan 18, 2011 at 3:47 AM, Jim Nasby <j...@nasby.net> wrote: > On Jan 16, 2011, at 4:37 PM, Kevin Grittner wrote: >> Robert Haas wrote: >> >>> a quick-and-dirty attempt to limit the amount of I/O caused by hint >>> bits. I'm still very interested in knowing what people think about >>> that. >> >> I found the elimination of the response-time spike promising. I >> don't think I've seen enough data yet to feel comfortable endorsing >> it, though. I guess the question in my head is: how much of the >> lingering performance hit was due to having to go to clog and how >> much was due to competition with the deferred writes? If much of it >> is due to repeated recalculation of visibility based on clog info, I >> think there would need to be some way to limit how many times that >> happened before the hint bits were saved. > > What if we sped up the case where hint bits aren't set? Has anyone collected > data on the actual pain points of checking visibility when hint bits aren't > set?
I think that's worth looking into, but I don't have any present plan to actually do it. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
