diff options
Diffstat (limited to 'src/backend/optimizer/path/indxpath.c')
| -rw-r--r-- | src/backend/optimizer/path/indxpath.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index edb16ce0d6d..8c63d9e1c38 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.80 2000/02/15 20:49:16 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.81 2000/03/22 22:08:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1454,6 +1454,26 @@ index_innerjoin(Query *root, RelOptInfo *rel, IndexOptInfo *index, /* joinrelids saves the rels needed on the outer side of the join */ pathnode->joinrelids = lfirst(outerrelids_list); + /* + * We must compute the estimated number of output rows for the + * indexscan. This is less than rel->rows because of the additional + * selectivity of the join clauses. Since clausegroup may contain + * both restriction and join clauses, we have to do a set union to + * get the full set of clauses that must be considered to compute + * the correct selectivity. (We can't just nconc the two lists; + * then we might have some restriction clauses appearing twice, + * which'd mislead restrictlist_selectivity into double-counting + * their selectivity.) + */ + pathnode->rows = rel->tuples * + restrictlist_selectivity(root, + LispUnion(rel->baserestrictinfo, + clausegroup), + lfirsti(rel->relids)); + /* Like costsize.c, force estimate to be at least one row */ + if (pathnode->rows < 1.0) + pathnode->rows = 1.0; + cost_index(&pathnode->path, root, rel, index, indexquals, true); path_list = lappend(path_list, pathnode); |