diff options
Diffstat (limited to 'src/backend/optimizer/path/allpaths.c')
| -rw-r--r-- | src/backend/optimizer/path/allpaths.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index cc8ba61bb0c..2e4b670e069 100644 --- a/src/backend/optimizer/path/allpaths.c +++ b/src/backend/optimizer/path/allpaths.c @@ -15,6 +15,7 @@ #include "postgres.h" +#include <limits.h> #include <math.h> #include "access/sysattr.h" @@ -56,6 +57,7 @@ typedef struct pushdown_safety_info /* These parameters are set by GUC */ bool enable_geqo = false; /* just in case GUC doesn't set it */ int geqo_threshold; +int min_parallel_relation_size; /* Hook for plugins to get control in set_rel_pathlist() */ set_rel_pathlist_hook_type set_rel_pathlist_hook = NULL; @@ -690,7 +692,7 @@ create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel) parallel_workers = rel->rel_parallel_workers; else { - int parallel_threshold = 1000; + int parallel_threshold; /* * If this relation is too small to be worth a parallel scan, just @@ -699,21 +701,24 @@ create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel) * might not be worthwhile just for this relation, but when combined * with all of its inheritance siblings it may well pay off. */ - if (rel->pages < parallel_threshold && + if (rel->pages < (BlockNumber) min_parallel_relation_size && rel->reloptkind == RELOPT_BASEREL) return; /* * Select the number of workers based on the log of the size of the * relation. This probably needs to be a good deal more - * sophisticated, but we need something here for now. + * sophisticated, but we need something here for now. Note that the + * upper limit of the min_parallel_relation_size GUC is chosen to + * prevent overflow here. */ parallel_workers = 1; - while (rel->pages > parallel_threshold * 3) + parallel_threshold = Max(min_parallel_relation_size, 1); + while (rel->pages >= (BlockNumber) (parallel_threshold * 3)) { parallel_workers++; parallel_threshold *= 3; - if (parallel_threshold >= PG_INT32_MAX / 3) + if (parallel_threshold > INT_MAX / 3) break; /* avoid overflow */ } } |