From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mitch Skinner <mitch@egcrc.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: same plan, add 1 condition, 1900x slower
Date: Thu, 10 Nov 2005 12:23:20 -0500
Message-ID: <10164.1131643400@sss.pgh.pa.us> (raw)
In-Reply-To: <1131630176.29496.91.camel@enzian>
References: <1131630176.29496.91.camel@enzian>
Mitch Skinner <mitch@egcrc.net> writes:
> This is with Postgres 8.0.3. Any advice is appreciated.
These are exactly the same plan, except for the addition of the extra
filter condition ...
> -> Index Scan using external_id_map_primary_key on external_id_map
> eim (cost=0.00..2345747.01 rows=15560708 width=26) (actual
> time=0.061..2.944 rows=2175 loops=1)
> -> Index Scan using external_id_map_primary_key on external_id_map
> eim (cost=0.00..2384648.78 rows=4150 width=26) (actual
> time=0.020..21068.508 rows=1186 loops=1)
> Filter: (source = 'SCH'::bpchar)
Apparently, you are using a platform and/or locale in which strcoll() is
spectacularly, god-awfully slow --- on the order of 10 msec per comparison.
This is a bit hard to believe but I can't make sense of those numbers
any other way. What is the platform exactly, and what database locale
and encoding are you using?
regards, tom lane
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, mitch@egcrc.net
Subject: Re: same plan, add 1 condition, 1900x slower
In-Reply-To: <10164.1131643400@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox