Re: Possible to improve query plan?

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От Jayadevan M
Тема Re: Possible to improve query plan?
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Msg-id OFCF071F4A.48152E2C-ON6525781B.002EEEE4-6525781B.002FFBBE@ibsplc.com
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Ответ на Possible to improve query plan?  (Jeremy Palmer <JPalmer@linz.govt.nz>)
Список pgsql-performance
Hello,

>
> The distribution of the data is that all but 120,000 rows have null
> values in the _revision_expired column.
>

A shot in the dark - will a partial index on the above column help?
http://www.postgresql.org/docs/current/interactive/indexes-partial.html
http://en.wikipedia.org/wiki/Partial_index

One link with discussion about it...
http://www.devheads.net/database/postgresql/general/when-can-postgresql-use-partial-not-null-index-seems-depend-size-clause-even-enable-seqscan.htm

Regards,
Jayadevan





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