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Add bitmap info:

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<   heap page to find matching rows.
>   heap page to find matching rows, or perhaps use a mixed solution where
>   tids are recorded for pages with only a few matches and per-page bitmaps
>   are used for more dense pages.  Another idea is to use a 32-bit bitmap
>   for every page and set a bit based on the item number mod(32).
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Bruce Momjian 2004-11-10 02:48:41 +00:00
parent 9a633cbb6c
commit 056d7e3a18
1 changed files with 5 additions and 2 deletions
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@ -6,7 +6,7 @@ TODO list for PostgreSQL
Bracketed items "[]" have more detail. Bracketed items "[]" have more detail.
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
Last updated: Tue Nov 9 11:50:52 EST 2004 Last updated: Tue Nov 9 21:48:31 EST 2004
The most recent version of this document can be viewed at the PostgreSQL web The most recent version of this document can be viewed at the PostgreSQL web
site, http://www.PostgreSQL.org. site, http://www.PostgreSQL.org.
@ -256,7 +256,10 @@ Indexes
indexes to dynamically create a composite index to match a specific query. 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 Each index is a bitmap, and the bitmaps are bitwise AND'ed or OR'ed to be
combined. They can index by tid or can be lossy requiring a scan of the combined. They can index by tid or can be lossy requiring a scan of the
heap page to find matching rows. heap page to find matching rows, or perhaps use a mixed solution where
tids are recorded for pages with only a few matches and per-page bitmaps
are used for more dense pages. Another idea is to use a 32-bit bitmap
for every page and set a bit based on the item number mod(32).
* Allow the creation of on-disk bitmap indexes which can be quickly * Allow the creation of on-disk bitmap indexes which can be quickly
combined with other bitmap indexes combined with other bitmap indexes