Re: Single client performance on trivial SELECTs

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Greg Smith <greg@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2011-04-14T21:10:41Z
Lists: pgsql-hackers
Noah Misch <noah@leadboat.com> writes:
> On Thu, Apr 14, 2011 at 11:15:00AM -0700, Robert Haas wrote:
>> It shouldn't be
>> terribly difficult to come up with some kind of hash function based
>> on, say, the first two characters of the keyword that would be a lot
>> faster than what we're doing now.

> I'd look at `gperf', which generates code for this from your keyword list.

FWIW, mysql used to use gperf for this purpose, but they've abandoned it
in favor of some homegrown hashing scheme.  I don't know exactly why,
but I wonder if it was for licensing reasons.  gperf itself is GPL, and
I don't see any disclaimer in the docs saying that its output isn't.

			regards, tom lane