From: Henrik Thostrup Jensen <htj@nordu.net>
To: Jeff Janes <jeff.janes@gmail.com>
To: Emre Hasegeli <emre@hasegeli.com>
To: pgsql-performance <pgsql-performance@postgresql.org>
Subject: Re: Gist indexing performance with cidr types
Date: Thu, 27 Aug 2015 11:35:31 +0200 (CEST)
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On Wed, 26 Aug 2015, Jeff Janes wrote:
> Any chance you can share the actual underlying data?
Sure. I added a snapshot to the repo:
https://github.com/job/irrexplorer/blob/master/data/irrexplorer_dump.sql.gz?raw=true> I noticed it wasn't on github, but is that because it is proprietary, or
> just because you don't think it is interesting?
I hoped it wouldn't be this complicated :-).
BGP and IRR data is (mostly) public, but it changes constantly, so there
is little sense in putting in the repo, as it is not the authorative
source (we have a script to boostrap with instead).
> If you loop over the 732 rows yourself, issuing the simple query against each retrieved constant value:
>
> explain (analyze,buffers) select routes.route from routes where route && $1
>
> Does each one take about the same amount of time, or are there some outlier values which take much more time than the others?
I wrote a small script to try this out. It queries for each route 20 times
to try and suppress the worst noise. I've sorted the results by time and
put it here: https://gist.github.com/htj/1817883f92a9cb17a4f8
(ignore the ntp timing issue causing a negative value)
Some observations:
- v6 is faster than v4 which is expected.
- The slowest prefixes by all seem to start bits '11'.
However it is only by a factor of 1.5x which is not really significant
Best regards, Henrik
Henrik Thostrup Jensen <htj at nordu.net>
Software Developer, NORDUnet
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To: pgsql-performance@postgresql.org
Cc: htj@nordu.net, jeff.janes@gmail.com, emre@hasegeli.com
Subject: Re: Gist indexing performance with cidr types
In-Reply-To: <alpine.DEB.2.11.1508271121170.3739@pyrite>
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