diff options
Diffstat (limited to 'src/backend/utils/adt/selfuncs.c')
| -rw-r--r-- | src/backend/utils/adt/selfuncs.c | 43 |
1 files changed, 31 insertions, 12 deletions
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index ab41413432c..30106744ded 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -15,7 +15,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.54 2000/01/26 05:57:14 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.55 2000/02/15 20:49:21 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -756,7 +756,9 @@ getattstatistics(Oid relid, static void genericcostestimate(Query *root, RelOptInfo *rel, IndexOptInfo *index, List *indexQuals, - Cost *indexAccessCost, Selectivity *indexSelectivity) + Cost *indexStartupCost, + Cost *indexTotalCost, + Selectivity *indexSelectivity) { double numIndexTuples; double numIndexPages; @@ -771,8 +773,17 @@ genericcostestimate(Query *root, RelOptInfo *rel, /* Estimate the number of index pages that will be retrieved */ numIndexPages = *indexSelectivity * index->pages; - /* Compute the index access cost */ - *indexAccessCost = numIndexPages + cpu_index_page_weight * numIndexTuples; + /* + * Compute the index access cost. + * + * Our generic assumption is that the index pages will be read + * sequentially, so they have cost 1.0 each, not random_page_cost. + * Also, we charge for evaluation of the indexquals at each index tuple. + * All the costs are assumed to be paid incrementally during the scan. + */ + *indexStartupCost = 0; + *indexTotalCost = numIndexPages + + (cpu_index_tuple_cost + cost_qual_eval(indexQuals)) * numIndexTuples; } /* @@ -782,35 +793,43 @@ genericcostestimate(Query *root, RelOptInfo *rel, void btcostestimate(Query *root, RelOptInfo *rel, IndexOptInfo *index, List *indexQuals, - Cost *indexAccessCost, Selectivity *indexSelectivity) + Cost *indexStartupCost, + Cost *indexTotalCost, + Selectivity *indexSelectivity) { genericcostestimate(root, rel, index, indexQuals, - indexAccessCost, indexSelectivity); + indexStartupCost, indexTotalCost, indexSelectivity); } void rtcostestimate(Query *root, RelOptInfo *rel, IndexOptInfo *index, List *indexQuals, - Cost *indexAccessCost, Selectivity *indexSelectivity) + Cost *indexStartupCost, + Cost *indexTotalCost, + Selectivity *indexSelectivity) { genericcostestimate(root, rel, index, indexQuals, - indexAccessCost, indexSelectivity); + indexStartupCost, indexTotalCost, indexSelectivity); } void hashcostestimate(Query *root, RelOptInfo *rel, IndexOptInfo *index, List *indexQuals, - Cost *indexAccessCost, Selectivity *indexSelectivity) + Cost *indexStartupCost, + Cost *indexTotalCost, + Selectivity *indexSelectivity) { genericcostestimate(root, rel, index, indexQuals, - indexAccessCost, indexSelectivity); + indexStartupCost, indexTotalCost, indexSelectivity); } void gistcostestimate(Query *root, RelOptInfo *rel, IndexOptInfo *index, List *indexQuals, - Cost *indexAccessCost, Selectivity *indexSelectivity) + Cost *indexStartupCost, + Cost *indexTotalCost, + Selectivity *indexSelectivity) { genericcostestimate(root, rel, index, indexQuals, - indexAccessCost, indexSelectivity); + indexStartupCost, indexTotalCost, indexSelectivity); } |