Re: Question about Bitmap Heap Scan/BitmapAnd

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От Guillaume Smet
Тема Re: Question about Bitmap Heap Scan/BitmapAnd
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Msg-id 1d4e0c10702151632o3846869rddb0a9f83adfcadd@mail.gmail.com
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Ответ на Re: Question about Bitmap Heap Scan/BitmapAnd  ("Guillaume Smet" <guillaume.smet@gmail.com>)
Список pgsql-performance
On 2/15/07, Guillaume Smet <guillaume.smet@gmail.com> wrote:
> On 2/15/07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > I think that the
> > answer is probably "because the index is lossy for this operator,
> > so it has to be checked even if the bitmap didn't become lossy".
> > You'd have to check the GIST opclass definition to be sure.

FYI I've taken a look at PostGIS source code and the index is lossy
for the operator &&:
OPERATOR        3        &&    RECHECK,

(for every operator in the opclass to be exact)

--
Guillaume

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