From: | Jasen Betts <jasen(at)xnet(dot)co(dot)nz> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Need advice to avoid ORDER BY |
Date: | 2013-04-06 05:57:41 |
Message-ID: | kjodgl$3uf$3@gonzo.reversiblemaps.ath.cx |
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Lists: | pgsql-general |
On 2013-04-04, Condor <condor(at)stz-bg(dot)com> wrote:
> Hello,
>
> I have one query in my postgresql 9.2.3 that took 137 ms to me executed
> and looking a way
> what I can do to optimize it. I have one table generated numbers from 1
> to 1 000 000 and
> I need to get first free id, meanwhile id's when is taken can be free
> (deleted data and id
> is free for next job). Table is simple:
>
>
> id serial,
> jobid text,
> valids int default 0
>
> (Yes, I have index).
>
>
> my query is: SELECT jobid FROM mytable WHERE valids = 0 ORDER BY id ASC
> LIMIT 1
>
> I need the first id only.
>
> My question is: Is there a way how I can avoid using ORDER BY to
> receive the first
> free id from mytable ?
create index freejobs on mytable(id) where valids = 0 ;
retry the same query.
--
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