Re: Query optimisation

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От Craig Ringer
Тема Re: Query optimisation
Дата
Msg-id 47F9A67A.9090903@postnewspapers.com.au
обсуждение исходный текст
Ответ на Query optimisation  (Naz Gassiep <naz@mira.net>)
Ответы Re: Query optimisation  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: Query optimisation  (Naz Gassiep <naz@mira.net>)
Список pgsql-general
Naz Gassiep wrote:

>                 JOIN files imageid_file ON (images.imageid =
> imageid_file.fileid)
>                 JOIN files size120_file ON (images.size120 =
> size120_file.fileid)
>                 JOIN files size240_file ON (images.size240 =
> size240_file.fileid)
>                 JOIN files size420_file ON (images.size420 =
> size420_file.fileid)
>                 JOIN files size600_file ON (images.size600 =
> size600_file.fileid)
>                 JOIN files size800_file ON (images.size800 =
> size800_file.fileid)
>                 JOIN files size1024_file ON (images.size1024 =
> size1024_file.fileid)
>                 JOIN files size130sq_file ON (images.size130sq =
> size130sq_file.fileid)
>                 JOIN files size240sq_file ON (images.size240sq =
> size240sq_file.fileid)
>                 JOIN files size420sq_file ON (images.size420sq =
> size420sq_file.fileid)
>                 JOIN images_sites ON (images_sites.imageid =
> images.imageid)

That's a whole lot of joins.

Do all those tables have the same fields? Can you unify them into one
table with an additional field like "imagesize" and use an appropriate
WHERE clause when looking up the table?

--
Craig Ringer

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