Re: Postgres refusing to use >1 core

From: Aren Cambre <aren(at)arencambre(dot)com>
To: Eric McKeeth <eldin00(at)gmail(dot)com>
Cc: Craig Ringer <craig(at)postnewspapers(dot)com(dot)au>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Postgres refusing to use >1 core
Date: 2011-05-12 18:27:44
Message-ID: BANLkTikAPLv_oU7rFVODTyv887hSsGHJNQ@mail.gmail.com
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>
> This is a perfect example of a place where you could push some work out of
> the application and into the database. You can consolidate your 1 to 101
> queries into a single query. If you use:
>
> WHERE rte_nm='SH71' AND rm >= 206 AND rm <= 306 ORDER BY abs(rm - 256), rm
> - 256 DESC LIMIT 1
>
> it will always return the same value as the first matching query from your
> list, and will never have to make more than one trip to the database. Your
> one trip might be slightly slower than any one of the single trips above,
> but it will certainly be much faster in the case where you have to hit any
> significant % of your 101 potential queries.
>

THANKS!! I've been obsessing so much about parallelism that I hadn't spent
much time finding better queries.

Aren

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