Re: index use

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От Stephan Szabo
Тема Re: index use
Дата
Msg-id 20041119122810.X44886@megazone.bigpanda.com
обсуждение исходный текст
Ответ на index use  (Arshavir Grigorian <ag@m-cam.com>)
Список pgsql-performance
On Fri, 19 Nov 2004, Arshavir Grigorian wrote:

> Hi,
>
> I have a query that when run on similar tables in 2 different databases
> either uses the index on the column (primary key) in the where clause or
> does a full table scan. The structure of the tables is the same, except
> that the table where the index does not get used has an extra million
> rows (22mil vs 23mil).
>
> The 2 boxes where these database run are very different (Sparc with scsi
> disks and 2G RAM running Solaris 8 AND a PC with 128M RAM running and an
> IDE drive running Linux RH9 2.4.20-20.9). I am not sure why that would
> make a difference, but maybe it does.

Is the second server running in "C" locale or a different locale? The
optimization for LIKE to use indexes involves either making an index with
a *_pattern_ops operator class or being in "C" locale.

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