From 4e023373d0dc5d38b058c1a208188131cd9af902 Mon Sep 17 00:00:00 2001 From: Bruce Momjian <bruce@momjian.us> Date: Sat, 2 Jun 2007 11:28:01 +0000 Subject: [PATCH] Re-add TODO and clarify it is for the kernel cache: < * Allow free-behind capability for large sequential scans, perhaps using < posix_fadvise() > * Allow free-behind capability for large sequential scans to avoid > kernel cache spoiling --- doc/TODO | 10 +++++++++- doc/src/FAQ/TODO.html | 11 +++++++++-- 2 files changed, 18 insertions(+), 3 deletions(-) diff --git a/doc/TODO b/doc/TODO index 2fdce435dad..4a5b9b8eca6 100644 --- a/doc/TODO +++ b/doc/TODO @@ -1,7 +1,7 @@ PostgreSQL TODO List ==================== Current maintainer: Bruce Momjian (bruce@momjian.us) -Last updated: Fri Jun 1 22:46:01 EDT 2007 +Last updated: Sat Jun 2 07:27:46 EDT 2007 The most recent version of this document can be viewed at http://www.postgresql.org/docs/faqs.TODO.html. @@ -1090,6 +1090,14 @@ Fsync Cache Usage =========== +* Allow free-behind capability for large sequential scans to avoid + kernel cache spoiling + + Posix_fadvise() can control both sequential/random file caching and + free-behind behavior, but it is unclear how the setting affects other + backends that also have the file open, and the feature is not supported + on all operating systems. + * Speed up COUNT(*) We could use a fixed row count and a +/- count to follow MVCC diff --git a/doc/src/FAQ/TODO.html b/doc/src/FAQ/TODO.html index a1d458e21b2..90dd0171e0a 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: Fri Jun 1 22:46:01 EDT 2007 +Last updated: Sat Jun 2 07:27:46 EDT 2007 </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>. @@ -971,7 +971,14 @@ first. There is also a developer's wiki at<br/> <h1><a name="section_14">Cache Usage</a></h1> <ul> - <li>Speed up COUNT(*) + <li>Allow free-behind capability for large sequential scans to avoid + kernel cache spoiling +<p> Posix_fadvise() can control both sequential/random file caching and + free-behind behavior, but it is unclear how the setting affects other + backends that also have the file open, and the feature is not supported + on all operating systems. +</p> + </li><li>Speed up COUNT(*) <p> We could use a fixed row count and a +/- count to follow MVCC visibility rules, or a single cached value could be used and invalidated if anyone modifies the table. Another idea is to -- GitLab