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Revise cost_qual_eval() to compute both startup (one-time) and per-tuple

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costs for expression evaluation, not only per-tuple cost as before.
This extension is needed in order to deal realistically with hashed or
materialized sub-selects.
This commit is contained in:
Tom Lane
2003-01-12 22:35:29 +00:00
parent d51260aa9d
commit d4ce5a4f4c
8 changed files with 164 additions and 71 deletions
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8
src/backend/utils/adt/selfuncs.c
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@ -15,7 +15,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.124 2002/12/17 01:18:35 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.125 2003/01/12 22:35:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -3757,6 +3757,7 @@ genericcostestimate(Query *root, RelOptInfo *rel,
{
double numIndexTuples;
double numIndexPages;
QualCost index_qual_cost;
List *selectivityQuals = indexQuals;
/*
@ -3826,9 +3827,10 @@ genericcostestimate(Query *root, RelOptInfo *rel,
* tuple. All the costs are assumed to be paid incrementally during
* the scan.
*/
*indexStartupCost = 0;
cost_qual_eval(&index_qual_cost, indexQuals);
*indexStartupCost = index_qual_cost.startup;
*indexTotalCost = numIndexPages +
(cpu_index_tuple_cost + cost_qual_eval(indexQuals)) * numIndexTuples;
(cpu_index_tuple_cost + index_qual_cost.per_tuple) * numIndexTuples;
/*
* Generic assumption about index correlation: there isn't any.