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Adjust costsize calculations to avoid introducing unnecessary roundoff 

error.  This seems to explain the differing choice of plan that's been
causing geometry regress test to fail for the last few days.
This commit is contained in:
Tom Lane 2002-12-13 17:29:25 +00:00
parent 023ff17178
commit 77b7a740f9
1 changed files with 42 additions and 18 deletions
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60
src/backend/optimizer/path/costsize.c
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@ -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 1.94 2002/12/12 15:49:28 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/costsize.c,v 1.95 2002/12/13 17:29:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -672,12 +672,22 @@ cost_nestloop(Path *path, Query *root,
*/
startup_cost += outer_path->startup_cost + inner_path->startup_cost;
run_cost += outer_path->total_cost - outer_path->startup_cost;
run_cost += outer_path->parent->rows *
(inner_path->total_cost - inner_path->startup_cost);
if (!(IsA(inner_path, MaterialPath) ||
IsA(inner_path, HashPath)) &&
outer_path->parent->rows > 1)
run_cost += (outer_path->parent->rows - 1) * inner_path->startup_cost;
if (IsA(inner_path, MaterialPath) ||
IsA(inner_path, HashPath))
{
/* charge only run cost for each iteration of inner path */
run_cost += outer_path->parent->rows *
(inner_path->total_cost - inner_path->startup_cost);
}
else
{
/*
* charge total cost for each iteration of inner path, except we
* already charged the first startup_cost in our own startup
*/
run_cost += outer_path->parent->rows * inner_path->total_cost
- inner_path->startup_cost;
}
/*
* Number of tuples processed (not number emitted!). If inner path is
@ -768,8 +778,8 @@ cost_mergejoin(Path *path, Query *root,
innerscansel = firstclause->left_mergescansel;
}
outer_rows = outer_path->parent->rows * outerscansel;
inner_rows = inner_path->parent->rows * innerscansel;
outer_rows = ceil(outer_path->parent->rows * outerscansel);
inner_rows = ceil(inner_path->parent->rows * innerscansel);
/* cost of source data */
@ -1343,10 +1353,12 @@ approx_selectivity(Query *root, List *quals)
void
set_baserel_size_estimates(Query *root, RelOptInfo *rel)
{
double temp;
/* Should only be applied to base relations */
Assert(length(rel->relids) == 1);
rel->rows = rel->tuples *
temp = rel->tuples *
restrictlist_selectivity(root,
rel->baserestrictinfo,
lfirsti(rel->relids));
@ -1354,10 +1366,14 @@ set_baserel_size_estimates(Query *root, RelOptInfo *rel)
/*
* Force estimate to be at least one row, to make explain output look
* better and to avoid possible divide-by-zero when interpolating
* cost.
* cost. Make it an integer, too.
*/
if (rel->rows < 1.0)
rel->rows = 1.0;
if (temp < 1.0)
temp = 1.0;
else
temp = ceil(temp);
rel->rows = temp;
rel->baserestrictcost = cost_qual_eval(rel->baserestrictinfo);
@ -1437,10 +1453,12 @@ set_joinrel_size_estimates(Query *root, RelOptInfo *rel,
/*
* Force estimate to be at least one row, to make explain output look
* better and to avoid possible divide-by-zero when interpolating
* cost.
* cost. Make it an integer, too.
*/
if (temp < 1.0)
temp = 1.0;
else
temp = ceil(temp);
rel->rows = temp;
@ -1470,6 +1488,8 @@ set_joinrel_size_estimates(Query *root, RelOptInfo *rel,
void
set_function_size_estimates(Query *root, RelOptInfo *rel)
{
double temp;
/* Should only be applied to base relations that are functions */
Assert(length(rel->relids) == 1);
Assert(rel->rtekind == RTE_FUNCTION);
@ -1483,7 +1503,7 @@ set_function_size_estimates(Query *root, RelOptInfo *rel)
rel->tuples = 1000;
/* Now estimate number of output rows */
rel->rows = rel->tuples *
temp = rel->tuples *
restrictlist_selectivity(root,
rel->baserestrictinfo,
lfirsti(rel->relids));
@ -1491,10 +1511,14 @@ set_function_size_estimates(Query *root, RelOptInfo *rel)
/*
* Force estimate to be at least one row, to make explain output look
* better and to avoid possible divide-by-zero when interpolating
* cost.
* cost. Make it an integer, too.
*/
if (rel->rows < 1.0)
rel->rows = 1.0;
if (temp < 1.0)
temp = 1.0;
else
temp = ceil(temp);
rel->rows = temp;
rel->baserestrictcost = cost_qual_eval(rel->baserestrictinfo);