Re: [PATCHES] ARC Memory Usage analysis
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jan Wieck <JanWieck@Yahoo.com>
Cc: Simon Riggs <simon@2ndquadrant.com>, pgsql-patches@postgresql.org, pgsql-hackers@postgresql.org, josh@agliodbs.com
Date: 2004-10-22T20:45:51Z
Lists: pgsql-hackers, pgsql-performance
Jan Wieck <JanWieck@Yahoo.com> writes: > What do you think about my other theory to make C actually 2x effective > cache size and NOT to keep T1 in shared buffers but to assume T1 lives > in the OS buffer cache? What will you do when initially fetching a page? It's not supposed to go directly into T2 on first use, but we're going to have some difficulty accessing a page that's not in shared buffers. I don't think you can equate the T1/T2 dichotomy to "is in shared buffers or not". You could maybe have a T3 list of "pages that aren't in shared buffers anymore but we think are still in OS buffer cache", but what would be the point? It'd be a sufficiently bad model of reality as to be pretty much useless for stats gathering, I'd think. regards, tom lane