diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index e464e66878a5fbf580641ca87e258dc71a6151ed..f81c920d26d3afcf6a8b6da30810b2270c912533 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.
diff --git a/src/backend/optimizer/geqo/geqo_main.c b/src/backend/optimizer/geqo/geqo_main.c
index 9b16c4a06e6ee140fc892a982de8bc45289834ba..6a883fa313799ac8e26e570967deea764a61d414 100644
--- a/src/backend/optimizer/geqo/geqo_main.c
+++ b/src/backend/optimizer/geqo/geqo_main.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/optimizer/geqo/geqo_main.c,v 1.41 2003/11/29 19:51:50 pgsql Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/geqo/geqo_main.c,v 1.42 2004/01/21 23:33:34 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -38,13 +38,13 @@
* Configuration options
*/
int Geqo_pool_size;
-int Geqo_effort;
int Geqo_generations;
+int Geqo_effort;
double Geqo_selection_bias;
static int gimme_pool_size(int nr_rel);
-static int gimme_number_generations(int pool_size, int effort);
+static int gimme_number_generations(int pool_size);
/* define edge recombination crossover [ERX] per default */
#if !defined(ERX) && \
@@ -92,7 +92,7 @@ geqo(Query *root, int number_of_rels, List *initial_rels)
/* set GA parameters */
pool_size = gimme_pool_size(number_of_rels);
- number_generations = gimme_number_generations(pool_size, Geqo_effort);
+ number_generations = gimme_number_generations(pool_size);
status_interval = 10;
/* allocate genetic pool memory */
@@ -284,7 +284,7 @@ gimme_pool_size(int nr_rel)
{
double size;
- if (Geqo_pool_size != 0)
+ if (Geqo_pool_size > 0)
return Geqo_pool_size;
size = pow(2.0, nr_rel + 1.0);
@@ -305,10 +305,20 @@ gimme_pool_size(int nr_rel)
* = Effort * Log2(PoolSize)
*/
static int
-gimme_number_generations(int pool_size, int effort)
+gimme_number_generations(int pool_size)
{
- if (Geqo_generations <= 0)
- return effort * (int) ceil(log((double) pool_size) / log(2.0));
- else
+ double gens;
+
+ if (Geqo_generations > 0)
return Geqo_generations;
+
+ gens = Geqo_effort * log((double) pool_size) / log(2.0);
+
+ /* bound it to a sane range */
+ if (gens <= 0)
+ gens = 1;
+ else if (gens > 10000)
+ gens = 10000;
+
+ return (int) ceil(gens);
}
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 45bbfc96ea0b0e5b2d67210f5e97b1a0295c893b..2633bf9e4d3ec0573560de0eca5f1e60d92cdb4d 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
* Written by Peter Eisentraut <peter_e@gmx.net>.
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.177 2004/01/19 19:04:40 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.178 2004/01/21 23:33:34 tgl Exp $
*
*--------------------------------------------------------------------
*/
@@ -931,23 +931,23 @@ static struct config_int ConfigureNamesInt[] =
&Geqo_pool_size,
DEFAULT_GEQO_POOL_SIZE, 0, MAX_GEQO_POOL_SIZE, NULL, NULL
},
- {
- {"geqo_effort", PGC_USERSET, QUERY_TUNING_GEQO,
- gettext_noop("GEQO: effort is used to calculate a default for generations."),
- NULL
- },
- &Geqo_effort,
- 1, 1, INT_MAX, NULL, NULL
- },
{
{"geqo_generations", PGC_USERSET, QUERY_TUNING_GEQO,
- gettext_noop("GEQO: number of iterations in the algorithm."),
- gettext_noop("The number must be a positive integer. If 0 is "
+ gettext_noop("GEQO: number of iterations of the algorithm."),
+ gettext_noop("The value must be a positive integer. If 0 is "
"specified then effort * log2(poolsize) is used.")
},
&Geqo_generations,
0, 0, INT_MAX, NULL, NULL
},
+ {
+ {"geqo_effort", PGC_USERSET, QUERY_TUNING_GEQO,
+ gettext_noop("GEQO: effort is used to set the default for generations."),
+ NULL
+ },
+ &Geqo_effort,
+ DEFAULT_GEQO_EFFORT, MIN_GEQO_EFFORT, MAX_GEQO_EFFORT, NULL, NULL
+ },
{
{"deadlock_timeout", PGC_SIGHUP, LOCK_MANAGEMENT,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 98d4d76d3ae6bd65a778c1592e030ed18508a8bf..0fdf6b2e99fd2e46534ee75dd3a3d69704078bec 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -123,10 +123,10 @@
#geqo = true
#geqo_threshold = 11
-#geqo_effort = 1
-#geqo_generations = 0
#geqo_pool_size = 0 # default based on tables in statement,
# range 128-1024
+#geqo_generations = 0 # use default: effort * log2(pool_size)
+#geqo_effort = 40 # range 1-100
#geqo_selection_bias = 2.0 # range 1.5-2.0
# - Other Planner Options -
diff --git a/src/include/optimizer/geqo.h b/src/include/optimizer/geqo.h
index 249b477223031ccee00c5d175ee18ef4ff749d78..caa05f52ee971f9e53fd924440258ef22becf56d 100644
--- a/src/include/optimizer/geqo.h
+++ b/src/include/optimizer/geqo.h
@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/optimizer/geqo.h,v 1.33 2003/11/29 22:41:07 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/geqo.h,v 1.34 2004/01/21 23:33:34 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -44,22 +44,27 @@
/*
* Configuration options
+ *
+ * If you change these, update backend/utils/misc/postgresql.sample.conf
*/
-/* If you change these, update backend/utils/misc/postgresql.sample.conf */
extern int Geqo_pool_size;
#define DEFAULT_GEQO_POOL_SIZE 0 /* = default based on no. of relations. */
#define MIN_GEQO_POOL_SIZE 128
#define MAX_GEQO_POOL_SIZE 1024
-extern int Geqo_effort; /* 1 .. inf, only used to calculate
- * generations default */
extern int Geqo_generations; /* 1 .. inf, or 0 to use default based on
* pool size */
+extern int Geqo_effort; /* only used to calculate default for
+ * generations */
+
+#define DEFAULT_GEQO_EFFORT 40
+#define MIN_GEQO_EFFORT 1
+#define MAX_GEQO_EFFORT 100
+
extern double Geqo_selection_bias;
-/* If you change these, update backend/utils/misc/postgresql.sample.conf */
#define DEFAULT_GEQO_SELECTION_BIAS 2.0
#define MIN_GEQO_SELECTION_BIAS 1.5
#define MAX_GEQO_SELECTION_BIAS 2.0