diff options
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 14 | ||||
| -rw-r--r-- | src/test/regress/expected/select_distinct_on.out | 26 |
2 files changed, 22 insertions, 18 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index b5827d39808..62b2354f004 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -5300,8 +5300,11 @@ create_ordered_paths(PlannerInfo *root, limit_tuples); } - /* Add projection step if needed */ - if (sorted_path->pathtarget != target) + /* + * If the pathtarget of the result path has different expressions from + * the target to be applied, a projection step is needed. + */ + if (!equal(sorted_path->pathtarget->exprs, target->exprs)) sorted_path = apply_projection_to_path(root, ordered_rel, sorted_path, target); @@ -5378,8 +5381,11 @@ create_ordered_paths(PlannerInfo *root, root->sort_pathkeys, NULL, &total_groups); - /* Add projection step if needed */ - if (sorted_path->pathtarget != target) + /* + * If the pathtarget of the result path has different expressions + * from the target to be applied, a projection step is needed. + */ + if (!equal(sorted_path->pathtarget->exprs, target->exprs)) sorted_path = apply_projection_to_path(root, ordered_rel, sorted_path, target); diff --git a/src/test/regress/expected/select_distinct_on.out b/src/test/regress/expected/select_distinct_on.out index b2978c1114a..958381afe5e 100644 --- a/src/test/regress/expected/select_distinct_on.out +++ b/src/test/regress/expected/select_distinct_on.out @@ -81,13 +81,12 @@ select distinct on (1) floor(random()) as r, f1 from int4_tbl order by 1,2; EXPLAIN (COSTS OFF) SELECT DISTINCT ON (four) four,two FROM tenk1 WHERE four = 0 ORDER BY 1; - QUERY PLAN ----------------------------------- - Result - -> Limit - -> Seq Scan on tenk1 - Filter: (four = 0) -(4 rows) + QUERY PLAN +---------------------------- + Limit + -> Seq Scan on tenk1 + Filter: (four = 0) +(3 rows) -- and check the result of the above query is correct SELECT DISTINCT ON (four) four,two @@ -115,11 +114,10 @@ SELECT DISTINCT ON (four) four,two EXPLAIN (COSTS OFF) SELECT DISTINCT ON (four) four,hundred FROM tenk1 WHERE four = 0 ORDER BY 1,2; - QUERY PLAN ------------------------------------------------------ - Result - -> Limit - -> Index Scan using tenk1_hundred on tenk1 - Filter: (four = 0) -(4 rows) + QUERY PLAN +----------------------------------------------- + Limit + -> Index Scan using tenk1_hundred on tenk1 + Filter: (four = 0) +(3 rows) |