diff options
Diffstat (limited to 'src/backend/optimizer/path/costsize.c')
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 63 |
1 files changed, 62 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index 5f5e9ec3721..fffa25dd844 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -54,7 +54,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.164 2006/07/26 11:35:56 petere Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.165 2006/08/02 01:59:45 joe Exp $ * *------------------------------------------------------------------------- */ @@ -775,6 +775,36 @@ cost_functionscan(Path *path, PlannerInfo *root, RelOptInfo *baserel) } /* + * cost_valuesscan + * Determines and returns the cost of scanning a VALUES RTE. + */ +void +cost_valuesscan(Path *path, PlannerInfo *root, RelOptInfo *baserel) +{ + Cost startup_cost = 0; + Cost run_cost = 0; + Cost cpu_per_tuple; + + /* Should only be applied to base relations that are values lists */ + Assert(baserel->relid > 0); + Assert(baserel->rtekind == RTE_VALUES); + + /* + * For now, estimate list evaluation cost at one operator eval per + * list (probably pretty bogus, but is it worth being smarter?) + */ + cpu_per_tuple = cpu_operator_cost; + + /* Add scanning CPU costs */ + startup_cost += baserel->baserestrictcost.startup; + cpu_per_tuple += cpu_tuple_cost + baserel->baserestrictcost.per_tuple; + run_cost += cpu_per_tuple * baserel->tuples; + + path->startup_cost = startup_cost; + path->total_cost = startup_cost + run_cost; +} + +/* * cost_sort * Determines and returns the cost of sorting a relation, including * the cost of reading the input data. @@ -2023,6 +2053,37 @@ set_function_size_estimates(PlannerInfo *root, RelOptInfo *rel) set_baserel_size_estimates(root, rel); } +/* + * set_values_size_estimates + * Set the size estimates for a base relation that is a values list. + * + * The rel's targetlist and restrictinfo list must have been constructed + * already. + * + * We set the same fields as set_baserel_size_estimates. + */ +void +set_values_size_estimates(PlannerInfo *root, RelOptInfo *rel) +{ + RangeTblEntry *rte; + + /* Should only be applied to base relations that are values lists */ + Assert(rel->relid > 0); + rte = rt_fetch(rel->relid, root->parse->rtable); + Assert(rte->rtekind == RTE_VALUES); + + /* + * Estimate number of rows the values list will return. + * We know this precisely based on the list length (well, + * barring set-returning functions in list items, but that's + * a refinement not catered for anywhere else either). + */ + rel->tuples = list_length(rte->values_lists); + + /* Now estimate number of output rows, etc */ + set_baserel_size_estimates(root, rel); +} + /* * set_rel_width |