PostgreSQL TODO List

====================

Current maintainer:Bruce Momjian (pgman@candle.pha.pa.us)

Last updated:Thu Apr 2100:09:27 EDT 2005

Last updated:Thu Apr 2111:20:13 EDT 2005

The most recent version of this document can be viewed at the PostgreSQL web

site, http://www.PostgreSQL.org.

* Allow non-bitmap indexes to be combined by creating bitmaps in memory

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. They can index by tid or can be lossy requiring a scan of the

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 feature allows separate indexes to be ANDed or ORed together. This

is particularly useful for data warehousing applications that need to

query the database in an many permutations. This feature scans an index

and creates an in-memory bitmap, and allows that bitmap to be combined

with other bitmap created in a similar way. The bitmap can either index

all TIDs, or be lossy, meaning it records just page numbers and each

page tuple has to be checked for validity in a separate pass.

* Allow the creation of on-disk bitmap indexes which can be quickly

combined with other bitmap indexes

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<h1><aname="section_1">PostgreSQL TODO List</a></h1>

<p>Current maintainer: Bruce Momjian (<ahref="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</a>)<br/>

Last updated: Thu Apr 2100:09:27 EDT 2005

Last updated: Thu Apr 2111:20:13 EDT 2005

<p>The most recent version of this document can be viewed at the PostgreSQL web<br/>

site,<ahref="http://www.PostgreSQL.org">http://www.PostgreSQL.org</a>.

before accessing the heap rows.

</li><li>Allow non-bitmap indexes to be combined by creating bitmaps in memory

<p> 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. They can index by tid or can be lossy requiring a scan of the

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).

<p> This feature allows separate indexes to be ANDed or ORed together. This

is particularly useful for data warehousing applications that need to

query the database in an many permutations. This feature scans an index

and creates an in-memory bitmap, and allows that bitmap to be combined

with other bitmap created in a similar way. The bitmap can either index

all TIDs, or be lossy, meaning it records just page numbers and each

page tuple has to be checked for validity in a separate pass.

</li><li>Allow the creation of on-disk bitmap indexes which can be quickly

combined with other bitmap indexes