Re: tricky query

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От Merlin Moncure
Тема Re: tricky query
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Msg-id 6EE64EF3AB31D5448D0007DD34EEB3415C2BF8@Herge.rcsinc.local
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Ответ на tricky query  ("Merlin Moncure" <merlin.moncure@rcsonline.com>)
Список pgsql-performance
> Not so bad. Try something like this:
>
> SELECT min(id+1) as id_new FROM table
>     WHERE (id+1) NOT IN (SELECT id FROM table);
>
> Now, this requires probably a sequential scan, but I'm not sure how
you
> can get around that.
> Maybe if you got trickier and did some ordering and limits. The above
> seems to give the right answer, though.

it does, but it is still faster than generate_series(), which requires
both a seqscan and a materialization of the function.

> I don't know how big you want to scale to.

big. :)

merlin

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