Re: Regression in IN( field, field, field ) performance

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От Gregory Stark
Тема Re: Regression in IN( field, field, field ) performance
Дата
Msg-id 87wsg1sgo3.fsf@oxford.xeocode.com
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Ответ на Re: Regression in IN( field, field, field ) performance  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: Regression in IN( field, field, field ) performance  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane <tgl@sss.pgh.pa.us> writes:

> Works fine for me, eg
...
>    ->  Bitmap Heap Scan on tenk1 b  (cost=0.79..4.82 rows=3 width=244)
>          Recheck Cond: (b.unique2 = ANY (ARRAY[a.unique1, a.ten, a.hundred]))
>          ->  Bitmap Index Scan on tenk1_unique2  (cost=0.00..0.79 rows=3 width=0
> )
>                Index Cond: (b.unique2 = ANY (ARRAY[a.unique1, a.ten, a.hundred])

But that's an index on the lhs of the =ANY which in his example was just a
constant.

> You'll need to provide a concrete test case if you think there's
> something broken here.

I think he's looking for something like:
5 IN (col1,col2,col3)

resulting in a bitmap or of three index scans of three different indexes on
col1, col2, and col3.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com Ask me about EnterpriseDB's RemoteDBA services!


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