Remove geqo_random_seed parameter. Having geqo reset the global random()

sequence every time it's called is bogus --- it interferes with user
control over the seed, and actually decreases randomness overall
(because a seed based on time(NULL) is pretty predictable).  If you really
want a reproducible result from geqo, do 'set seed = 0' before planning
a query.

doc/src/sgml/runtime.sgml

 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.203 2003/09/05 16:13:38 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.204 2003/09/07 15:26:45 tgl Exp $
 -->
 
 <Chapter Id="runtime">
@@ -1438,7 +1438,6 @@ SET ENABLE_SEQSCAN TO OFF;
       <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_RANDOM_SEED</varname> (<type>integer</type>)</term>
       <term><varname>GEQO_SELECTION_BIAS</varname> (<type>floating point</type>)</term>
       <listitem>
        <para>
@@ -1455,9 +1454,7 @@ SET ENABLE_SEQSCAN TO OFF;
         is roughly proportional to the sum of pool size and generations.
         The selection bias is the selective pressure within the
         population. Values can be from 1.50 to 2.00; the latter is the
-        default. The random seed can be set to get reproducible results
-        from the algorithm. If it is set to -1 then the algorithm
-        behaves non-deterministically.
+        default.
        </para>
       </listitem>
      </varlistentry>

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
  *
- * $Header: /cvsroot/pgsql/src/backend/optimizer/geqo/geqo_main.c,v 1.39 2003/08/12 18:23:20 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/optimizer/geqo/geqo_main.c,v 1.40 2003/09/07 15:26:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -41,7 +41,6 @@ int			Geqo_pool_size;
 int			Geqo_effort;
 int			Geqo_generations;
 double		Geqo_selection_bias;
-int			Geqo_random_seed;
 
 
 static int	gimme_pool_size(int nr_rel);
@@ -96,13 +95,6 @@ geqo(Query *root, int number_of_rels, List *initial_rels)
 	number_generations = gimme_number_generations(pool_size, Geqo_effort);
 	status_interval = 10;
 
-/* seed random number generator */
-/* XXX why is this done every time around? */
-	if (Geqo_random_seed >= 0)
-		srandom((unsigned int) Geqo_random_seed);
-	else
-		srandom((unsigned int) time(NULL));
-
 /* allocate genetic pool memory */
 	pool = alloc_pool(pool_size, number_of_rels);
 

src/backend/utils/misc/guc.c

@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.155 2003/09/04 05:11:20 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.156 2003/09/07 15:26:53 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -898,15 +898,6 @@ static struct config_int ConfigureNamesInt[] =
 		&Geqo_generations,
 		0, 0, INT_MAX, NULL, NULL
 	},
-	{
-		{"geqo_random_seed", PGC_USERSET, QUERY_TUNING_GEQO,
-			gettext_noop("Can be set to get reproducible results from the algorithm"),
-			gettext_noop("If it is set to -1 then the algorithm behaves "
-						 "non-deterministically")
-		},
-		&Geqo_random_seed,
-		-1, INT_MIN, INT_MAX, NULL, NULL
-	},
 
 	{
 		{"deadlock_timeout", PGC_SIGHUP, LOCK_MANAGEMENT,

src/backend/utils/misc/postgresql.conf.sample

@@ -121,7 +121,6 @@
 #geqo_generations = 0
 #geqo_pool_size = 0		# default based on tables in statement,
 				# range 128-1024
-#geqo_random_seed = -1		# -1 = use variable seed
 #geqo_selection_bias = 2.0	# range 1.5-2.0
 
 # - Other Planner Options -

src/bin/psql/tab-complete.c

@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2000-2003, PostgreSQL Global Development Group
  *
- * $Header: /cvsroot/pgsql/src/bin/psql/tab-complete.c,v 1.84 2003/08/04 23:59:40 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/bin/psql/tab-complete.c,v 1.85 2003/09/07 15:26:54 tgl Exp $
  */
 
 /*----------------------------------------------------------------------
@@ -534,7 +534,6 @@ psql_completion(char *text, int start, int end)
 		"geqo_effort",
 		"geqo_generations",
 		"geqo_pool_size",
-		"geqo_random_seed",
 		"geqo_selection_bias",
 		"geqo_threshold",
 		"join_collapse_limit",

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
  *
- * $Id: geqo.h,v 1.31 2003/08/04 02:40:13 momjian Exp $
+ * $Id: geqo.h,v 1.32 2003/09/07 15:26:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -64,8 +64,6 @@ extern double Geqo_selection_bias;
 #define MIN_GEQO_SELECTION_BIAS 1.5
 #define MAX_GEQO_SELECTION_BIAS 2.0
 
-extern int	Geqo_random_seed;	/* or negative to use current time */
-
 
 /* routines in geqo_main.c */
 extern RelOptInfo *geqo(Query *root, int number_of_rels, List *initial_rels);