diff options
Diffstat (limited to 'src/backend/optimizer/geqo/geqo_main.c')
| -rw-r--r-- | src/backend/optimizer/geqo/geqo_main.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/src/backend/optimizer/geqo/geqo_main.c b/src/backend/optimizer/geqo/geqo_main.c index 9b16c4a06e..6a883fa313 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); } |