diff options
Diffstat (limited to 'src/backend/optimizer/path/costsize.c')
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index fa8d06707b..eec165ab5d 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 1.158 2006/06/06 17:59:57 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.159 2006/07/01 18:38:32 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1604,20 +1604,29 @@ cost_qual_eval(QualCost *cost, List *quals) * routine's use, so that it's not necessary to evaluate the qual * clause's cost more than once. If the clause's cost hasn't been * computed yet, the field's startup value will contain -1. + * + * If the RestrictInfo is marked pseudoconstant, it will be tested + * only once, so treat its cost as all startup cost. */ if (qual && IsA(qual, RestrictInfo)) { - RestrictInfo *restrictinfo = (RestrictInfo *) qual; + RestrictInfo *rinfo = (RestrictInfo *) qual; - if (restrictinfo->eval_cost.startup < 0) + if (rinfo->eval_cost.startup < 0) { - restrictinfo->eval_cost.startup = 0; - restrictinfo->eval_cost.per_tuple = 0; - cost_qual_eval_walker((Node *) restrictinfo->clause, - &restrictinfo->eval_cost); + rinfo->eval_cost.startup = 0; + rinfo->eval_cost.per_tuple = 0; + cost_qual_eval_walker((Node *) rinfo->clause, + &rinfo->eval_cost); + if (rinfo->pseudoconstant) + { + /* count one execution during startup */ + rinfo->eval_cost.startup += rinfo->eval_cost.per_tuple; + rinfo->eval_cost.per_tuple = 0; + } } - cost->startup += restrictinfo->eval_cost.startup; - cost->per_tuple += restrictinfo->eval_cost.per_tuple; + cost->startup += rinfo->eval_cost.startup; + cost->per_tuple += rinfo->eval_cost.per_tuple; } else { @@ -1876,7 +1885,9 @@ set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel, * * If we are doing an outer join, take that into account: the output must * be at least as large as the non-nullable input. (Is there any chance - * of being even smarter?) + * of being even smarter?) (XXX this is not really right, because it + * assumes all the restriction clauses are join clauses; we should figure + * pushed-down clauses separately.) * * For JOIN_IN and variants, the Cartesian product is figured with respect * to a unique-ified input, and then we can clamp to the size of the other |