diff options
Diffstat (limited to 'src/backend/optimizer/path/pathkeys.c')
| -rw-r--r-- | src/backend/optimizer/path/pathkeys.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index 6d1cc3b8a04..ec66cb9c3c5 100644 --- a/src/backend/optimizer/path/pathkeys.c +++ b/src/backend/optimizer/path/pathkeys.c @@ -447,8 +447,10 @@ get_cheapest_parallel_safe_total_inner(List *paths) * If 'scandir' is BackwardScanDirection, build pathkeys representing a * backwards scan of the index. * - * The result is canonical, meaning that redundant pathkeys are removed; - * it may therefore have fewer entries than there are index columns. + * We iterate only key columns of covering indexes, since non-key columns + * don't influence index ordering. The result is canonical, meaning that + * redundant pathkeys are removed; it may therefore have fewer entries than + * there are key columns in the index. * * Another reason for stopping early is that we may be able to tell that * an index column's sort order is uninteresting for this query. However, @@ -477,6 +479,13 @@ build_index_pathkeys(PlannerInfo *root, bool nulls_first; PathKey *cpathkey; + /* + * INCLUDE columns are stored in index unordered, so they don't + * support ordered index scan. + */ + if (i >= index->nkeycolumns) + break; + /* We assume we don't need to make a copy of the tlist item */ indexkey = indextle->expr; |