Repair error apparently introduced in the initial coding of GUC: the

default value for geqo_effort is supposed to be 40, not 1.  The actual
'genetic' component of the GEQO algorithm has been practically disabled
since 7.1 because of this mistake.  Improve documentation while at it.

1 files changed, 13 insertions, 11 deletions

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index e464e66878a..f81c920d26d 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.230 2004/01/10 23:28:43 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.231 2004/01/21 23:33:34 tgl Exp $
 -->
 
 <Chapter Id="runtime">
@@ -1404,23 +1404,25 @@ SET ENABLE_SEQSCAN TO OFF;
      </varlistentry>
 
      <varlistentry>
-      <term><varname>geqo_effort</varname> (<type>integer</type>)</term>
-      <term><varname>geqo_generations</varname> (<type>integer</type>)</term>
       <term><varname>geqo_pool_size</varname> (<type>integer</type>)</term>
+      <term><varname>geqo_generations</varname> (<type>integer</type>)</term>
+      <term><varname>geqo_effort</varname> (<type>integer</type>)</term>
       <term><varname>geqo_selection_bias</varname> (<type>floating point</type>)</term>
       <listitem>
        <para>
         Various tuning parameters for the genetic query optimization
-        algorithm: The pool size is the number of individuals in one
+        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 <literal>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 number must be a positive
-        integer. If 0 is specified then <literal>Effort *
-        Log2(PoolSize)</literal> is used. The run time of the algorithm
-        is roughly proportional to the sum of pool size and generations.
+        number of <literal>FROM</> items in the query, is used.
+	Generations specifies the number of iterations of the algorithm.
+	The value must be a positive integer. If 0 is specified then
+	<literal>Effort * Log2(PoolSize)</literal> is used.
+	The run time of the algorithm is roughly proportional to the sum of
+	pool size and generations.
+	<varname>geqo_effort</varname> is only used in computing the default
+	generations setting, as just described.  The default value is 40,
+	and the allowed range 1 to 100.
         The selection bias is the selective pressure within the
         population. Values can be from 1.50 to 2.00; the latter is the
         default.