diff options
Diffstat (limited to 'src/backend/optimizer/util/pathnode.c')
| -rw-r--r-- | src/backend/optimizer/util/pathnode.c | 30 |
1 files changed, 9 insertions, 21 deletions
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c index de5f2fda5b2..0edb1801498 100644 --- a/src/backend/optimizer/util/pathnode.c +++ b/src/backend/optimizer/util/pathnode.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/util/pathnode.c,v 1.50 1999/07/30 00:56:17 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/pathnode.c,v 1.51 1999/07/30 04:07:25 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -300,23 +300,20 @@ create_seqscan_path(RelOptInfo *rel) /* * create_index_path - * Creates a single path node for an index scan. + * Creates a path node for an index scan. * * 'rel' is the parent rel - * 'index' is the pathnode for the index on 'rel' - * 'restriction_clauses' is a list of restriction clause nodes. - * 'is_join_scan' is a flag indicating whether or not the index is being - * considered because of its sort order. + * 'index' is an index on 'rel' + * 'restriction_clauses' is a list of RestrictInfo nodes + * to be used as index qual conditions in the scan. * * Returns the new path node. - * */ IndexPath * create_index_path(Query *root, RelOptInfo *rel, RelOptInfo *index, - List *restriction_clauses, - bool is_join_scan) + List *restriction_clauses) { IndexPath *pathnode = makeNode(IndexPath); @@ -361,20 +358,11 @@ create_index_path(Query *root, else pathnode->path.pathkeys = NULL; - if (is_join_scan || restriction_clauses == NULL) + if (restriction_clauses == NIL) { /* - * Indices used for joins or sorting result nodes don't restrict - * the result at all, they simply order it, so compute the scan - * cost accordingly -- use a selectivity of 1.0. - * - * is the statement above really true? what about IndexScan as the - * inner of a join? - * - * I think it's OK --- this routine is only used to make index paths - * for mergejoins and sorts. Index paths used as the inner side of - * a nestloop join do provide restriction, but they are not made - * with this code. See index_innerjoin() in indxpath.c. + * We have no restriction clauses, so compute scan cost using + * selectivity of 1.0. */ pathnode->path.path_cost = cost_index(lfirsti(index->relids), index->pages, |