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.
This commit is contained in:
Bruce Momjian 2006-06-24 23:47:58 +00:00
parent fc6a2293b5
commit ac7a126d0c
2 changed files with 14 additions and 10 deletions

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@ -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

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@ -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