Re: Index AM change proposals, redux

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От Heikki Linnakangas
Тема Re: Index AM change proposals, redux
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Msg-id 4803655F.90005@enterprisedb.com
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Ответ на Re: Index AM change proposals, redux  (Ron Mayer <rm_pg@cheapcomplexdevices.com>)
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Ron Mayer wrote:
> Then I wonder if I can conceive of yet another related
> index type that'd be useful for such clustered tables.  If
> I had something like GIT that stored something like
> "values State='CA' can be found on pages 1000 through 10000
> and 20000 through 21000" would it be even more effective on
> such a table than GIT?

Yep, a bitmap index.

Bitmap indexes don't actually work quite like that, but the point is 
that it is very efficient on a column with few distinct values, and even 
more so if the table is clustered on that column.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com


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