Horton

Re: Clock sweep not caching enough B-Tree leaf pages?

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <pg@heroku.com>
Cc: Jim Nasby <jim@nasby.net>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@2ndquadrant.com>, Merlin Moncure <mmoncure@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2014-04-22T01:12:38Z
Lists: pgsql-hackers 
Peter Geoghegan <pg@heroku.com> writes:
> On Mon, Apr 21, 2014 at 5:50 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> ARC *was* the predecessor algorithm.  See commit 5d5087363.

> I believe that the main impetus for replacing ARC with clock sweep
> came from patent issues, though.

That was one issue, but performance gains were a large part of it too,
and the main reason why we picked clock sweep rather than something else.
Did you read the commit message I pointed to?

(See also 4e8af8d27.)

			regards, tom lane

Commits

  1. Replace the BufMgrLock with separate locks on the lookup hashtable and