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< * Use bitmaps to combine existing indexes [performance]
> * Allow the creation of bitmap indexes which can be quickly combined
>   with other bitmap indexes
255,257c256,266
<   Bitmap indexes allow single indexed columns to be combined to
<   dynamically create a composite index to match a specific query. Each
<   index is a bitmap, and the bitmaps are AND'ed or OR'ed to be combined.
>   Bitmap indexes index single columns that can be combined with other bitmap
>   indexes to dynamically create a composite index to match a specific query.
>   Each index is a bitmap, and the bitmaps are bitwise AND'ed or OR'ed to be
>   combined.  Such indexes could be more compact if there are few unique
>   value.  Also, perhaps they can be lossy requiring a scan of the heap page
>   to find matching rows.
>
> * Allow non-bitmap indexes to be combined
>
>   Do lookups on non-bitmap indexes and create bitmaps in memory that can be
>   combined with other indexes.
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Bruce Momjian 2004-11-04 03:57:58 +00:00
parent c21214f1c0
commit 4fbdfbffc6
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@ -5,7 +5,7 @@ TODO list for PostgreSQL
Bracketed items "[]" have more detail.
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
Last updated: Wed Nov 3 17:20:38 EST 2004
Last updated: Wed Nov 3 22:57:53 EST 2004
The most recent version of this document can be viewed at the PostgreSQL web
site, http://www.PostgreSQL.org.
@ -253,14 +253,18 @@ Indexes
* Allow the creation of bitmap indexes which can be quickly combined
with other bitmap indexes
Bitmap indexes index single columns and can be combined with other bitmap
Bitmap indexes index single columns that can be combined with other bitmap
indexes to dynamically create a composite index to match a specific query.
Each index is a bitmap, and the bitmaps are bitwise AND'ed or OR'ed to be
combined.
combined. Such indexes could be more compact if there are few unique
value. Also, perhaps they can be lossy requiring a scan of the heap page
to find matching rows.
* Allow non-bitmap indexes to be combined
Do loUse bitmaps to combine non-bitmap indexes
Do lookups on non-bitmap indexes and create bitmaps in memory that can be
combined with other indexes.
* Allow use of indexes to search for NULLs
One solution is to create a partial index on an IS NULL expression.