diff options
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 43 |
1 files changed, 29 insertions, 14 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index a94d54342e4..e215a6cd366 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -42,7 +42,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.81 2002/03/01 06:01:19 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.82 2002/03/01 20:50:20 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -467,10 +467,11 @@ cost_sort(Path *path, Query *root, } /* - * Note: should we bother to assign a nonzero run_cost to reflect the - * overhead of extracting tuples from the sort result? Probably not - * worth worrying about. + * Also charge a small amount (arbitrarily set equal to operator cost) + * per extracted tuple. */ + run_cost += cpu_operator_cost * tuples; + path->startup_cost = startup_cost; path->total_cost = startup_cost + run_cost; } @@ -567,11 +568,12 @@ cost_mergejoin(Path *path, Query *root, Cost run_cost = 0; Cost cpu_per_tuple; RestrictInfo *firstclause; + Var *leftvar; double outer_rows, inner_rows; double ntuples; - Selectivity leftscan, - rightscan; + Selectivity outerscansel, + innerscansel; Path sort_path; /* dummy for result of cost_sort */ if (!enable_mergejoin) @@ -592,11 +594,24 @@ cost_mergejoin(Path *path, Query *root, mergejoinscansel(root, (Node *) firstclause->clause, &firstclause->left_mergescansel, &firstclause->right_mergescansel); - leftscan = firstclause->left_mergescansel; - rightscan = firstclause->right_mergescansel; - outer_rows = outer_path->parent->rows * leftscan; - inner_rows = inner_path->parent->rows * rightscan; + leftvar = get_leftop(firstclause->clause); + Assert(IsA(leftvar, Var)); + if (intMember(leftvar->varno, outer_path->parent->relids)) + { + /* left side of clause is outer */ + outerscansel = firstclause->left_mergescansel; + innerscansel = firstclause->right_mergescansel; + } + else + { + /* left side of clause is inner */ + outerscansel = firstclause->right_mergescansel; + innerscansel = firstclause->left_mergescansel; + } + + outer_rows = outer_path->parent->rows * outerscansel; + inner_rows = inner_path->parent->rows * innerscansel; /* cost of source data */ @@ -616,13 +631,13 @@ cost_mergejoin(Path *path, Query *root, outer_path->parent->width); startup_cost += sort_path.startup_cost; run_cost += (sort_path.total_cost - sort_path.startup_cost) - * leftscan; + * outerscansel; } else { startup_cost += outer_path->startup_cost; run_cost += (outer_path->total_cost - outer_path->startup_cost) - * leftscan; + * outerscansel; } if (innersortkeys) /* do we need to sort inner? */ @@ -635,13 +650,13 @@ cost_mergejoin(Path *path, Query *root, inner_path->parent->width); startup_cost += sort_path.startup_cost; run_cost += (sort_path.total_cost - sort_path.startup_cost) - * rightscan; + * innerscansel; } else { startup_cost += inner_path->startup_cost; run_cost += (inner_path->total_cost - inner_path->startup_cost) - * rightscan; + * innerscansel; } /* |