diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 27 | ||||
| -rw-r--r-- | src/test/regress/expected/subselect.out | 29 | ||||
| -rw-r--r-- | src/test/regress/sql/subselect.sql | 11 |
3 files changed, 62 insertions, 5 deletions
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index d8cabbd5bfe..0f921186609 100644 --- a/src/backend/optimizer/plan/subselect.c +++ b/src/backend/optimizer/plan/subselect.c @@ -856,11 +856,6 @@ generate_subquery_vars(PlannerInfo *root, List *tlist, Index varno) * with Params or Vars representing the results of the sub-select. The * nodes to be substituted are passed in as the List result from * generate_subquery_params or generate_subquery_vars. - * - * The given testexpr has already been recursively processed by - * process_sublinks_mutator. Hence it can no longer contain any - * PARAM_SUBLINK Params for lower SubLink nodes; we can safely assume that - * any we find are for our own level of SubLink. */ static Node * convert_testexpr(PlannerInfo *root, @@ -899,6 +894,28 @@ convert_testexpr_mutator(Node *node, param->paramid - 1)); } } + if (IsA(node, SubLink)) + { + /* + * If we come across a nested SubLink, it is neither necessary nor + * correct to recurse into it: any PARAM_SUBLINKs we might find inside + * belong to the inner SubLink not the outer. So just return it as-is. + * + * This reasoning depends on the assumption that nothing will pull + * subexpressions into or out of the testexpr field of a SubLink, at + * least not without replacing PARAM_SUBLINKs first. If we did want + * to do that we'd need to rethink the parser-output representation + * altogether, since currently PARAM_SUBLINKs are only unique per + * SubLink not globally across the query. The whole point of + * replacing them with Vars or PARAM_EXEC nodes is to make them + * globally unique before they escape from the SubLink's testexpr. + * + * Note: this can't happen when called during SS_process_sublinks, + * because that recursively processes inner SubLinks first. It can + * happen when called from convert_ANY_sublink_to_join, though. + */ + return node; + } return expression_tree_mutator(node, convert_testexpr_mutator, (void *) context); diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out index 39c12f91e8c..ce15af7378b 100644 --- a/src/test/regress/expected/subselect.out +++ b/src/test/regress/expected/subselect.out @@ -710,3 +710,32 @@ select exists(select * from nocolumns); f (1 row) +-- +-- Check sane behavior with nested IN SubLinks +-- +explain (verbose, costs off) +select * from int4_tbl where + (case when f1 in (select unique1 from tenk1 a) then f1 else null end) in + (select ten from tenk1 b); + QUERY PLAN +--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- + Nested Loop Semi Join + Output: int4_tbl.f1 + Join Filter: (CASE WHEN (hashed SubPlan 1) THEN int4_tbl.f1 ELSE NULL::integer END = b.ten) + -> Seq Scan on public.int4_tbl + Output: int4_tbl.f1 + -> Seq Scan on public.tenk1 b + Output: b.unique1, b.unique2, b.two, b.four, b.ten, b.twenty, b.hundred, b.thousand, b.twothousand, b.fivethous, b.tenthous, b.odd, b.even, b.stringu1, b.stringu2, b.string4 + SubPlan 1 + -> Index Only Scan using tenk1_unique1 on public.tenk1 a + Output: a.unique1 +(10 rows) + +select * from int4_tbl where + (case when f1 in (select unique1 from tenk1 a) then f1 else null end) in + (select ten from tenk1 b); + f1 +---- + 0 +(1 row) + diff --git a/src/test/regress/sql/subselect.sql b/src/test/regress/sql/subselect.sql index 278580797ec..326fd70e4a0 100644 --- a/src/test/regress/sql/subselect.sql +++ b/src/test/regress/sql/subselect.sql @@ -411,3 +411,14 @@ explain (verbose, costs off) -- create temp table nocolumns(); select exists(select * from nocolumns); + +-- +-- Check sane behavior with nested IN SubLinks +-- +explain (verbose, costs off) +select * from int4_tbl where + (case when f1 in (select unique1 from tenk1 a) then f1 else null end) in + (select ten from tenk1 b); +select * from int4_tbl where + (case when f1 in (select unique1 from tenk1 a) then f1 else null end) in + (select ten from tenk1 b); |