diff options
Diffstat (limited to 'src/backend/optimizer/geqo/geqo_main.c')
| -rw-r--r-- | src/backend/optimizer/geqo/geqo_main.c | 82 |
1 files changed, 76 insertions, 6 deletions
diff --git a/src/backend/optimizer/geqo/geqo_main.c b/src/backend/optimizer/geqo/geqo_main.c index 4ea22b6bab4..b00e9823bd6 100644 --- a/src/backend/optimizer/geqo/geqo_main.c +++ b/src/backend/optimizer/geqo/geqo_main.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2000, PostgreSQL, Inc * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: geqo_main.c,v 1.20 2000/01/26 05:56:33 momjian Exp $ + * $Id: geqo_main.c,v 1.21 2000/05/31 00:28:19 petere Exp $ * *------------------------------------------------------------------------- */ @@ -23,12 +23,30 @@ /* -- parts of this are adapted from D. Whitley's Genitor algorithm -- */ #include "postgres.h" + +#include <time.h> +#include <math.h> + #include "optimizer/geqo.h" #include "optimizer/geqo_misc.h" #include "optimizer/geqo_pool.h" #include "optimizer/geqo_selection.h" +/* + * Configuration options + */ +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); +static int gimme_number_generations(int pool_size, int effort); + + /* define edge recombination crossover [ERX] per default */ #if !defined(ERX) && \ !defined(PMX) && \ @@ -81,13 +99,16 @@ geqo(Query *root) number_of_rels = length(root->base_rel_list); /* set GA parameters */ - geqo_params(number_of_rels);/* read "$PGDATA/pg_geqo" file */ - pool_size = PoolSize; - number_generations = Generations; + pool_size = gimme_pool_size(number_of_rels); + number_generations = gimme_number_generations(pool_size, Geqo_effort); status_interval = 10; /* seed random number generator */ - srandom(RandomSeed); +/* XXX why is this done every time around? */ + if (Geqo_random_seed >= 0) + srandom(Geqo_random_seed); + else + srandom(time(NULL)); /* initialize plan evaluator */ geqo_eval_startup(); @@ -146,7 +167,7 @@ geqo(Query *root) { /* SELECTION */ - geqo_selection(momma, daddy, pool, SelectionBias); /* using linear bias + geqo_selection(momma, daddy, pool, Geqo_selection_bias);/* using linear bias * function */ @@ -263,3 +284,52 @@ print_plan(best_plan, root); return best_rel; } + + + +/* + * Return either configured pool size or + * a good default based on query size (no. of relations) + * = 2^(QS+1) + * also constrain between 128 and 1024 + */ +static int +gimme_pool_size(int nr_rel) +{ + double size; + + if (Geqo_pool_size != 0) + { + if (Geqo_pool_size < MIN_GEQO_POOL_SIZE) + return MIN_GEQO_POOL_SIZE; + else if (Geqo_pool_size > MAX_GEQO_POOL_SIZE) + return MAX_GEQO_POOL_SIZE; + else + return Geqo_pool_size; + } + + size = pow(2.0, nr_rel + 1.0); + + if (size < MIN_GEQO_POOL_SIZE) + return MIN_GEQO_POOL_SIZE; + else if (size > MAX_GEQO_POOL_SIZE) + return MAX_GEQO_POOL_SIZE; + else + return (int) ceil(size); +} + + + +/* + * Return either configured number of generations or + * some reasonable default calculated on the fly. + * = Effort * Log2(PoolSize) + */ +static int +gimme_number_generations(int pool_size, int effort) +{ + if (Geqo_generations <= 0) + return effort * (int) ceil(log((double) pool_size) / log(2.0)); + else + return Geqo_generations; +} |