Add bitmap info:

<   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).
This commit is contained in:
Bruce Momjian 2004-11-10 02:48:41 +00:00
parent 9a633cbb6c
commit 056d7e3a18

View File

@ -6,7 +6,7 @@ TODO list for PostgreSQL
Bracketed items "[]" have more detail.
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
site, http://www.PostgreSQL.org.
@ -256,7 +256,10 @@ Indexes
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. 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
combined with other bitmap indexes