Re: Return of the Solaris vacuum polling problem -- anyone remember this?
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Josh Berkus <josh@agliodbs.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2010-08-18T19:07:59Z
Lists: pgsql-hackers
Josh Berkus <josh@agliodbs.com> writes: >> Rather, what you need to be thinking about is how >> come vacuum seems to be making lots of pages dirty on only one of these >> machines. > This is an anti-wraparound vacuum, so it could have something to do with > the hint bits. Maybe it's setting the freeze bit on every page, and > writing them one page at a time? That would explain all the writes, but it doesn't seem to explain why your two servers aren't behaving similarly. > Still don't understand the call to pollsys, even so, though. Most likely that's the libc implementation of the select()-based sleeps for vacuum_cost_delay. I'm still suspicious that the writes are eating more cost_delay points than you think. regards, tom lane