From ac7a126d0c261d4013f1c8ff55d0895353587dea Mon Sep 17 00:00:00 2001 From: Bruce Momjian <bruce@momjian.us> Date: Sat, 24 Jun 2006 23:47:58 +0000 Subject: [PATCH] Update entry: < * Allow heap reuse of UPDATEd rows if old and new versions are on the < same heap page? > * Allow heap reuse of UPDATEd rows if no indexed columns are changed, > and old and new versions are on the same heap page? < This is possible for same-page updates because a single index row < can point to both old and new values. > While vacuum handles DELETEs fine, updating of non-indexed columns, like > counters, are difficult for VACUUM to handle efficiently. This method > is possible for same-page updates because a single index row can be > used to point to both old and new values. --- doc/TODO | 12 +++++++----- doc/src/FAQ/TODO.html | 12 +++++++----- 2 files changed, 14 insertions(+), 10 deletions(-) diff --git a/doc/TODO b/doc/TODO index 826ef81869d..2b22d70b919 100644 --- a/doc/TODO +++ b/doc/TODO @@ -2,7 +2,7 @@ PostgreSQL TODO List ==================== Current maintainer: Bruce Momjian (bruce@momjian.us) -Last updated: Sat Jun 24 19:44:48 EDT 2006 +Last updated: Sat Jun 24 19:47:53 EDT 2006 The most recent version of this document can be viewed at http://www.postgresql.org/docs/faqs.TODO.html. @@ -1131,11 +1131,13 @@ Vacuum http://archives.postgresql.org/pgsql-patches/2006-03/msg00142.php -* Allow heap reuse of UPDATEd rows if old and new versions are on the - same heap page? +* Allow heap reuse of UPDATEd rows if no indexed columns are changed, + and old and new versions are on the same heap page? - This is possible for same-page updates because a single index row - can point to both old and new values. + While vacuum handles DELETEs fine, updating of non-indexed columns, like + counters, are difficult for VACUUM to handle efficiently. This method + is possible for same-page updates because a single index row can be + used to point to both old and new values. http://archives.postgresql.org/pgsql-hackers/2006-06/msg01305.php * Auto-vacuum diff --git a/doc/src/FAQ/TODO.html b/doc/src/FAQ/TODO.html index 78fb8077a73..76e32367e5b 100644 --- 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:bruce@momjian.us">bruce@momjian.us</a>)<br/> -Last updated: Sat Jun 24 19:44:48 EDT 2006 +Last updated: Sat Jun 24 19:47:53 EDT 2006 </p> <p>The most recent version of this document can be viewed at<br/> <a href="http://www.postgresql.org/docs/faqs.TODO.html">http://www.postgresql.org/docs/faqs.TODO.html</a>. @@ -1020,10 +1020,12 @@ first. </li><li>Consider shrinking expired tuples to just their headers <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-03/msg00142.php">http://archives.postgresql.org/pgsql-patches/2006-03/msg00142.php</a> </p> - </li><li>Allow heap reuse of UPDATEd rows if old and new versions are on the - same heap page? -<p> This is possible for same-page updates because a single index row - can point to both old and new values. + </li><li>Allow heap reuse of UPDATEd rows if no indexed columns are changed, + and old and new versions are on the same heap page? +<p> While vacuum handles DELETEs fine, updating of non-indexed columns, like + counters, are difficult for VACUUM to handle efficiently. This method + is possible for same-page updates because a single index row can be + used to point to both old and new values. <a href="http://archives.postgresql.org/pgsql-hackers/2006-06/msg01305.php">http://archives.postgresql.org/pgsql-hackers/2006-06/msg01305.php</a> </p> </li><li>Auto-vacuum -- GitLab