Re: Clock sweep not caching enough B-Tree leaf pages?
Stephen Frost <sfrost@snowman.net>
From: Stephen Frost <sfrost@snowman.net>
To: Andres Freund <andres@2ndquadrant.com>
Cc: Heikki Linnakangas <hlinnakangas@vmware.com>,
Greg Stark <stark@mit.edu>, Robert Haas <robertmhaas@gmail.com>,
Peter Geoghegan <pg@heroku.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2014-04-17T18:54:21Z
Lists: pgsql-hackers
* Andres Freund (andres@2ndquadrant.com) wrote: > > Note that if we somehow come up with a page replacement algorithm that tends > > to evict pages that are in the OS cache, we have effectively solved the > > double buffering problem. When a page is cached in both caches, evicting it > > from one of them eliminates the double buffering. Granted, you might prefer > > to evict it from the OS cache instead, and such an algorithm could be bad in > > other ways. But if a page replacement algorithm happens avoid double > > buffering, that's a genuine merit for that algorithm. > > I don't think it's a good idea to try to synchronize algorithms with the > OSs. There's so much change about the caching logic in e.g. linux that > it won't stay effective for very long. There's also more than one OS... Thanks, Stephen
Commits
-
Replace the BufMgrLock with separate locks on the lookup hashtable and
- 5d5087363d7c 8.1.0 cited