diff options
Diffstat (limited to 'src/backend/optimizer')
| -rw-r--r-- | src/backend/optimizer/geqo/geqo_random.c | 23 | ||||
| -rw-r--r-- | src/backend/optimizer/geqo/geqo_selection.c | 14 |
2 files changed, 19 insertions, 18 deletions
diff --git a/src/backend/optimizer/geqo/geqo_random.c b/src/backend/optimizer/geqo/geqo_random.c index f21bc047e68..4d9432c0dfe 100644 --- a/src/backend/optimizer/geqo/geqo_random.c +++ b/src/backend/optimizer/geqo/geqo_random.c @@ -21,14 +21,7 @@ geqo_set_seed(PlannerInfo *root, double seed) { GeqoPrivateData *private = (GeqoPrivateData *) root->join_search_private; - /* - * XXX. This seeding algorithm could certainly be improved - but it is not - * critical to do so. - */ - memset(private->random_state, 0, sizeof(private->random_state)); - memcpy(private->random_state, - &seed, - Min(sizeof(private->random_state), sizeof(seed))); + pg_prng_fseed(&private->random_state, seed); } double @@ -36,5 +29,17 @@ geqo_rand(PlannerInfo *root) { GeqoPrivateData *private = (GeqoPrivateData *) root->join_search_private; - return pg_erand48(private->random_state); + return pg_prng_double(&private->random_state); +} + +int +geqo_randint(PlannerInfo *root, int upper, int lower) +{ + GeqoPrivateData *private = (GeqoPrivateData *) root->join_search_private; + + /* + * In current usage, "lower" is never negative so we can just use + * pg_prng_uint64_range directly. + */ + return (int) pg_prng_uint64_range(&private->random_state, lower, upper); } diff --git a/src/backend/optimizer/geqo/geqo_selection.c b/src/backend/optimizer/geqo/geqo_selection.c index 66b6c8ae38e..68a2e4e9f15 100644 --- a/src/backend/optimizer/geqo/geqo_selection.c +++ b/src/backend/optimizer/geqo/geqo_selection.c @@ -63,10 +63,6 @@ geqo_selection(PlannerInfo *root, Chromosome *momma, Chromosome *daddy, /* * Ensure we have selected different genes, except if pool size is only * one, when we can't. - * - * This code was observed to hang up in an infinite loop when the - * platform's implementation of erand48() was broken. We now always use - * our own version. */ if (pool->size > 1) { @@ -95,11 +91,11 @@ linear_rand(PlannerInfo *root, int pool_size, double bias) double max = (double) pool_size; /* - * If geqo_rand() returns exactly 1.0 then we will get exactly max from - * this equation, whereas we need 0 <= index < max. Also it seems - * possible that roundoff error might deliver values slightly outside the - * range; in particular avoid passing a value slightly less than 0 to - * sqrt(). If we get a bad value just try again. + * geqo_rand() is not supposed to return 1.0, but if it does then we will + * get exactly max from this equation, whereas we need 0 <= index < max. + * Also it seems possible that roundoff error might deliver values + * slightly outside the range; in particular avoid passing a value + * slightly less than 0 to sqrt(). If we get a bad value just try again. */ do { |