Re: left join with smaller table or index on (XXX is not null) to avoid upsert

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От Grzegorz Jaśkiewicz
Тема Re: left join with smaller table or index on (XXX is not null) to avoid upsert
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Msg-id 2f4958ff0901182312g3841445dn3c53fb008bb5faed@mail.gmail.com
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Ответ на Re: left join with smaller table or index on (XXX is not null) to avoid upsert  ("Scott Marlowe" <scott.marlowe@gmail.com>)
Ответы Re: left join with smaller table or index on (XXX is not null) to avoid upsert
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On Mon, Jan 19, 2009 at 2:44 AM, Scott Marlowe <scott.marlowe@gmail.com> wrote:
> Watch out for bloat when doing this.  A simple where change of
>
> update table set b = 45 ;
>
> to
>
> update table set b = 45 where b <> 45 ;
>
> can save the db a lot of work, and if you can apply the same logic to
> your update to save some dead tuples it's worth looking into.

I wonder why DB can't do it on its own :)

--
GJ

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