| From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
|---|---|
| To: | Rajesh Kumar Mallah <mallah(at)trade-india(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: IN surpasses NOT EXISTS in 7.4RC2 ?? |
| Date: | 2003-11-13 14:56:57 |
| Message-ID: | 200311131456.hADEuv409079@candle.pha.pa.us |
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| Lists: | pgsql-performance |
Rajesh Kumar Mallah wrote:
>
> Hi,
>
> NOT EXISTS is taking almost double time than NOT IN .
> I know IN has been optimised in 7.4 but is anything
> wrong with the NOT EXISTS?
>
> I have vaccumed , analyze and run the query many times
> still not in is faster than exists :>
Seems fine. In 7.4, NOT IN will often be faster that NOT EXISTS. NOT
EXISTS didn't change --- there are restrictions on how far we can
optimize NOT EXISTS. NOT IN has just become much faster in 7.4.
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
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