Horton

Re: Per-column collation

Peter Eisentraut <peter_e@gmx.net>

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From: Peter Eisentraut <peter_e@gmx.net>
To: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: Pavel Stehule <pavel.stehule@gmail.com>, pgsql-hackers@postgresql.org
Date: 2010-11-22T20:06:43Z
Lists: pgsql-hackers 
On tor, 2010-11-18 at 21:37 +0200, Heikki Linnakangas wrote:
> Have you done any performance testing? Functions like text_cmp can be
> a hotspot in sorting, so any extra overhead there might be show up in
> tests.

Without having optimized it very much yet, the performance for a 1GB
ORDER BY is

* without COLLATE clause: about the same as without the patch

* with COLLATE clause: about 30%-50% slower

I can imagine that there is some optimization potential in the latter
case.  But in any case, it's not awfully slow.