From 48beecda7cbd2e73ebc11c88d3567ad064604bda Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 7 Sep 2003 15:26:54 +0000 Subject: [PATCH] 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 | 7 ++----- src/backend/optimizer/geqo/geqo_main.c | 10 +--------- src/backend/utils/misc/guc.c | 11 +---------- src/backend/utils/misc/postgresql.conf.sample | 1 - src/bin/psql/tab-complete.c | 3 +-- src/include/optimizer/geqo.h | 4 +--- 6 files changed, 6 insertions(+), 30 deletions(-) diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml index 9bbecfa76b..425036d81d 100644 --- a/doc/src/sgml/runtime.sgml +++ b/doc/src/sgml/runtime.sgml @@ -1,5 +1,5 @@ @@ -1438,7 +1438,6 @@ SET ENABLE_SEQSCAN TO OFF; GEQO_EFFORT (integer) GEQO_GENERATIONS (integer) GEQO_POOL_SIZE (integer) - GEQO_RANDOM_SEED (integer) GEQO_SELECTION_BIAS (floating point) @@ -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. diff --git a/src/backend/optimizer/geqo/geqo_main.c b/src/backend/optimizer/geqo/geqo_main.c index d657fdf8db..031cd665d4 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 * - * $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); diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 2129042ed2..709f3090d1 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -10,7 +10,7 @@ * Written by Peter Eisentraut . * * 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, diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index a30ae074a1..c04aaab39b 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/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 - diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c index bcc52be98b..f6174a73f2 100644 --- a/src/bin/psql/tab-complete.c +++ b/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", diff --git a/src/include/optimizer/geqo.h b/src/include/optimizer/geqo.h index 0ead9dc304..53a2334a17 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 * - * $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);