From: Gregory Stark <stark@enterprisedb.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Guillaume Smet <guillaume.smet@gmail.com>
Cc: pgsql-performance <pgsql-performance@postgresql.org>
Cc: pgsql-hackers@postgresql.org
Subject: Re: Estimation problem with a LIKE clause containing a /
Date: Thu, 08 Nov 2007 23:10:49 +0000
Message-ID: <87prykpc3q.fsf@oxford.xeocode.com> (raw)
In-Reply-To: <27405.1194542548@sss.pgh.pa.us>
References: <1d4e0c10711070453q214f089cpd144cbb5193d3c4f@mail.gmail.com>
<17767.1194453292@sss.pgh.pa.us>
<11467.1194477248@sss.pgh.pa.us>
<1d4e0c10711080208n6c9875b4tf5882da3ced18532@mail.gmail.com>
<27405.1194542548@sss.pgh.pa.us>
"Tom Lane" <tgl@sss.pgh.pa.us> writes:
> What I am tempted to do about this is have make_greater_string tack "zz"
> onto the supplied prefix, so that it would have to find a string that
> compares greater than "123/zz" before reporting success. This is
> getting pretty klugy though, so cc'ing to pgsql-hackers to see if anyone
> has a better idea.
Hm, instead of "zz" is there a convenient way to find out what actual
character sorts last amongst all the single characters in the locale's
encoding?
Doesn't really strike at the core reason that this is so klugy though. Surely
the "right" thing is to push the concept of open versus closed end-points
through deeper into the estimation logic?
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
Ask me about EnterpriseDB's RemoteDBA services!
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: stark@enterprisedb.com, tgl@sss.pgh.pa.us, guillaume.smet@gmail.com, pgsql-hackers@postgresql.org
Subject: Re: Estimation problem with a LIKE clause containing a /
In-Reply-To: <87prykpc3q.fsf@oxford.xeocode.com>
* 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