From 21deb428970ea6225d3122207c3910a01f84c770 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 15 Feb 2001 04:28:50 +0000
Subject: [PATCH] Clarify meaning of GEQO_THRESHOLD parameter.
---
doc/src/sgml/runtime.sgml | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 4322a1f42e1..e26662117e1 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.50 2001/02/10 00:50:18 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.51 2001/02/15 04:28:50 tgl Exp $
-->
<Chapter Id="runtime">
@@ -639,7 +639,7 @@ env PGOPTIONS='-c geqo=off' psql
algorithm: The pool size is the number of individuals in one
population. Valid values are between 128 and 1024. If it is
set to 0 (the default) a pool size of 2^(QS+1), where QS
- is the number of relations in the query, is taken. The effort
+ is the number of FROM items in the query, is taken. The effort
is used to calculate a default for generations. Valid values
are between 1 and 80, 40 being the default. Generations
specifies the number of iterations in the algorithm. The
@@ -659,9 +659,10 @@ env PGOPTIONS='-c geqo=off' psql
<term>GEQO_THRESHOLD (<type>integer</type>)</term>
<listitem>
<para>
- Only use genetic query optimization for queries with at least
- this many relations involved. The default is 11. For less
- relations it is probably more efficient to use the
+ Use genetic query optimization to plan queries with at least
+ this many FROM items involved. (Note that a JOIN construct
+ counts as only one FROM item.) The default is 11. For simpler
+ queries it is usually best to use the
deterministic, exhaustive planner.
</para>
</listitem>
--
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