Re: Need advice to avoid ORDER BY

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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