Re: Single client performance on trivial SELECTs - Mailing list pgsql-hackers

From Noah Misch
Subject Re: Single client performance on trivial SELECTs
Date
Msg-id 20110414194526.GA5979@tornado.leadboat.com
Whole thread Raw
In response to Re: Single client performance on trivial SELECTs  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Single client performance on trivial SELECTs  (Robert Haas <robertmhaas@gmail.com>)
Re: Single client performance on trivial SELECTs  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Thu, Apr 14, 2011 at 11:15:00AM -0700, Robert Haas wrote:
> It's fairly far down in the noise on this particular profile, but in
> the low-hanging fruit department, I think we should fix
> ScanKeywordLookup to use a smarter algorithm that is more like O(1)
> rather than O(lg n) in the number of keywords.

+1

> 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.


pgsql-hackers by date:

Previous
From: Heikki Linnakangas
Date:
Subject: Re: Single client performance on trivial SELECTs
Next
From: Tom Lane
Date:
Subject: Re: Single client performance on trivial SELECTs