Re: ARC patent
Neil Conway <neilc@samurai.com>
From: Neil Conway <neilc@samurai.com>
To: Andrew Dunstan <andrew@dunslane.net>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Bruce Momjian <pgman@candle.pha.pa.us>, Andrew Sullivan <ajs@crankycanuck.ca>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2005-01-18T22:33:49Z
Lists: pgsql-hackers
On Mon, 2005-01-17 at 15:11 -0500, Andrew Dunstan wrote: > There's a very recent paper at > http://carmen.cs.uiuc.edu/~zchen9/paper/TPDS-final.ps on an alternative > to ARC which claims superior performance ... >From a quick glance, this doesn't look applicable. The authors are discussing buffer replacement strategies for a multi-level cache hierarchy (e.g. they would call the DBMS buffer cache "L1", and the kernel I/O cache "L2" -- note that despite the terminology, this has little in common with L1/L2 caches in processors). They don't really address caching for the L1-only case -- they're concerned with proposing algorithms to manage the L2 cache (with or without explicit knowledge about the content of the L1 cache). A few years ago Tom implemented the LRU-K replacement policy[1], but AFAIK the performance results from that weren't very positive (since the implementation of LRU-K requires a heap and is therefore logarithmic rather than constant time, that makes sense). The 2Q algorithm looks like it might be worth investigating[2]. -Neil [1] http://citeseer.ist.psu.edu/16869.html [2] http://citeseer.ist.psu.edu/63909.html