Updated text for bitmaps:

< 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.

Updated text for bitmaps:
< 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.
c6221db3 · Bruce Momjian · 631e0314 · c6221db3 · c6221db3
Commit c6221db3 authored Apr 21, 2005 by Bruce Momjian
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doc/TODO doc/TODO +8 -9

doc/src/FAQ/TODO.html doc/src/FAQ/TODO.html +8 -9

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--- a/doc/TODO
+++ b/doc/TODO
@@ -2,7 +2,7 @@
 PostgreSQL TODO List
 ====================
 Current maintainer:	Bruce Momjian (pgman@candle.pha.pa.us)
-Last updated:		Thu Apr 21 00:09:27 EDT 2005
+Last updated:		Thu Apr 21 11:20:13 EDT 2005

 The most recent version of this document can be viewed at the PostgreSQL web
 site, http://www.PostgreSQL.org.
@@ -300,14 +300,13 @@ Indexes

 * 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

--- a/doc/src/FAQ/TODO.html
+++ b/doc/src/FAQ/TODO.html
@@ -8,7 +8,7 @@
 <body bgcolor="#FFFFFF" text="#000000" link="#FF0000" vlink="#A00000" alink="#0000FF">
 <h1><a name="section_1">PostgreSQL TODO List</a></h1>
 <p>Current maintainer:     Bruce Momjian (<a href="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</a>)<br/>
-Last updated:           Thu Apr 21 00:09:27 EDT 2005
+Last updated:           Thu Apr 21 11:20:13 EDT 2005
 </p>
 <p>The most recent version of this document can be viewed at the PostgreSQL web<br/>
 site, <a href="http://www.PostgreSQL.org">http://www.PostgreSQL.org</a>.
@@ -277,14 +277,13 @@ first.
  before accessing the heap rows.
 </p>
  </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.
 </p>
  </li><li>Allow the creation of on-disk bitmap indexes which can be quickly
  combined with other bitmap indexes