Richard Huxton <dev@archonet.com> writes:
> Dirk Försterling wrote:
> > There were some dumb queries with timestamps, performing much slower
> > with Linux-2.6.5 compared to Linux-2.4.25:
> > The queries used something like this (ts is a TIMESTAMP):
> > ... AND ts LIKE '2003-04-%'
>
> I'm guessing an index isn't being used because your LANG is something-UTF-8 and
> that got picked up when you recreated your database. Try recreating the
> database with the C locale and see if that does it.
Uhm, under no locale would an index be used for "ts LIKE '2003-04-%'" unless
you have an functional index on ts::text, which would be kind of weird.
You might want to rewrite this as
ts BETWEEN '2003-04-01' AND '2003-04-01'+'1 month'
or something like that. At least this way a straight normal index on ts would
be usable work.
--
greg
---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
