Re: Many to many join seems slow?

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От Daniel Cristian Cruz
Тема Re: Many to many join seems slow?
Дата
Msg-id 48d0cacb0705150900o29f11b42t5dc5634be50e496a@mail.gmail.com
обсуждение исходный текст
Ответ на Many to many join seems slow?  (Drew Wilson <drewmwilson@gmail.com>)
Ответы Re: Many to many join seems slow?
Список pgsql-performance
2007/5/15, Drew Wilson <drewmwilson@gmail.com>:
> =# explain SELECT s.source_id, s.value AS sourceValue, t.value AS
> translationValue
>        FROM
>            source s,
>            translation_pair tp,
>            translation t,
>            language l
>        WHERE
>            s.source_id = tp.source_id
>            AND tp.translation_id = t.translation_id
>            AND t.language_id = l.language_id
>            AND l.name = 'French' ;
>
>                                                           QUERY PLAN
> ------------------------------------------------------------------------
> -----------------------------------------------------
> Merge Join  (cost=524224.49..732216.29 rows=92447 width=97)

This way you get all word matches for the French language. Shouldn't
it be all matches for a specific word (s.value = 'word' in WHERE)?

--
Daniel Cristian Cruz

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