diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/optimizer/path/indxpath.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index 750515fc348..73ac3d416b7 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -756,6 +756,7 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel, List *index_pathkeys; List *useful_pathkeys; bool found_clause; + bool found_lower_saop_clause; bool pathkeys_possibly_useful; bool index_is_ordered; bool index_only_scan; @@ -793,12 +794,20 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel, * if saop_control is SAOP_REQUIRE, it has to be a ScalarArrayOpExpr * clause. * + * found_lower_saop_clause is set true if there's a ScalarArrayOpExpr + * index clause for a non-first index column. This prevents us from + * assuming that the scan result is ordered. (Actually, the result is + * still ordered if there are equality constraints for all earlier + * columns, but it seems too expensive and non-modular for this code to be + * aware of that refinement.) + * * We also build a Relids set showing which outer rels are required by the * selected clauses. */ index_clauses = NIL; clause_columns = NIL; found_clause = false; + found_lower_saop_clause = false; outer_relids = NULL; for (indexcol = 0; indexcol < index->ncolumns; indexcol++) { @@ -814,6 +823,8 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel, if (saop_control == SAOP_PER_AM && !index->amsearcharray) continue; found_clause = true; + if (indexcol > 0) + found_lower_saop_clause = true; } else { @@ -850,9 +861,11 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel, /* * 2. Compute pathkeys describing index's ordering, if any, then see how * many of them are actually useful for this query. This is not relevant - * if we are only trying to build bitmap indexscans. + * if we are only trying to build bitmap indexscans, nor if we have to + * assume the scan is unordered. */ pathkeys_possibly_useful = (scantype != ST_BITMAPSCAN && + !found_lower_saop_clause && has_useful_pathkeys(root, rel)); index_is_ordered = (index->sortopfamily != NULL); if (index_is_ordered && pathkeys_possibly_useful) |