diff options
| -rw-r--r-- | src/backend/optimizer/path/allpaths.c | 21 | ||||
| -rw-r--r-- | src/test/regress/expected/union.out | 21 | ||||
| -rw-r--r-- | src/test/regress/sql/union.sql | 11 |
3 files changed, 53 insertions, 0 deletions
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index b11b9399891..40129016260 100644 --- a/src/backend/optimizer/path/allpaths.c +++ b/src/backend/optimizer/path/allpaths.c @@ -1307,6 +1307,8 @@ add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel, { List *subpaths = NIL; bool subpaths_valid = true; + List *startup_subpaths = NIL; + bool startup_subpaths_valid = true; List *partial_subpaths = NIL; List *pa_partial_subpaths = NIL; List *pa_nonpartial_subpaths = NIL; @@ -1346,6 +1348,20 @@ add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel, else subpaths_valid = false; + /* + * When the planner is considering cheap startup plans, we'll also + * collect all the cheapest_startup_paths and build an AppendPath + * containing those as subpaths. + */ + if (rel->consider_startup && childrel->pathlist != NIL && + childrel->cheapest_startup_path->param_info == NULL) + accumulate_append_subpath(childrel->cheapest_startup_path, + &startup_subpaths, + NULL); + else + startup_subpaths_valid = false; + + /* Same idea, but for a partial plan. */ if (childrel->partial_pathlist != NIL) { @@ -1478,6 +1494,11 @@ add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel, NIL, NULL, 0, false, -1)); + /* build an AppendPath for the cheap startup paths, if valid */ + if (startup_subpaths_valid) + add_path(rel, (Path *) create_append_path(root, rel, startup_subpaths, + NIL, NIL, NULL, 0, false, -1)); + /* * Consider an append of unordered, unparameterized partial paths. Make * it parallel-aware if possible. diff --git a/src/test/regress/expected/union.out b/src/test/regress/expected/union.out index e2613d6777e..f046e522dea 100644 --- a/src/test/regress/expected/union.out +++ b/src/test/regress/expected/union.out @@ -1432,3 +1432,24 @@ where (x = 0) or (q1 >= q2 and q1 <= q2); 4567890123456789 | 4567890123456789 | 1 (6 rows) +-- +-- Test the planner's ability to produce cheap startup plans with Append nodes +-- +-- Ensure we get a Nested Loop join between tenk1 and tenk2 +explain (costs off) +select t1.unique1 from tenk1 t1 +inner join tenk2 t2 on t1.tenthous = t2.tenthous + union all +(values(1)) limit 1; + QUERY PLAN +-------------------------------------------------------- + Limit + -> Append + -> Nested Loop + Join Filter: (t1.tenthous = t2.tenthous) + -> Seq Scan on tenk1 t1 + -> Materialize + -> Seq Scan on tenk2 t2 + -> Result +(8 rows) + diff --git a/src/test/regress/sql/union.sql b/src/test/regress/sql/union.sql index ca8c9b4d128..d65ca9f86de 100644 --- a/src/test/regress/sql/union.sql +++ b/src/test/regress/sql/union.sql @@ -540,3 +540,14 @@ select * from union all select *, 1 as x from int8_tbl b) ss where (x = 0) or (q1 >= q2 and q1 <= q2); + +-- +-- Test the planner's ability to produce cheap startup plans with Append nodes +-- + +-- Ensure we get a Nested Loop join between tenk1 and tenk2 +explain (costs off) +select t1.unique1 from tenk1 t1 +inner join tenk2 t2 on t1.tenthous = t2.tenthous + union all +(values(1)) limit 1;
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