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-rw-r--r--src/backend/optimizer/plan/createplan.c2
-rw-r--r--src/backend/utils/adt/ruleutils.c39
-rw-r--r--src/test/regress/expected/rowtypes.out54
-rw-r--r--src/test/regress/sql/rowtypes.sql21
4 files changed, 105 insertions, 11 deletions
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index e7d50f20b16..b5f1c2f4155 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -1831,7 +1831,7 @@ create_projection_plan(PlannerInfo *root, ProjectionPath *best_path, int flags)
* Convert our subpath to a Plan and determine whether we need a Result
* node.
*
- * In most cases where we don't need to project, creation_projection_path
+ * In most cases where we don't need to project, create_projection_path
* will have set dummypp, but not always. First, some createplan.c
* routines change the tlists of their nodes. (An example is that
* create_merge_append_plan might add resjunk sort columns to a
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index a19e6ce3c3f..cbaed0ceda9 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -7219,17 +7219,29 @@ get_name_for_var_field(Var *var, int fieldno,
/*
* We're deparsing a Plan tree so we don't have complete
* RTE entries (in particular, rte->subquery is NULL). But
- * the only place we'd see a Var directly referencing a
- * SUBQUERY RTE is in a SubqueryScan plan node, and we can
- * look into the child plan's tlist instead.
+ * the only place we'd normally see a Var directly
+ * referencing a SUBQUERY RTE is in a SubqueryScan plan
+ * node, and we can look into the child plan's tlist
+ * instead. An exception occurs if the subquery was
+ * proven empty and optimized away: then we'd find such a
+ * Var in a childless Result node, and there's nothing in
+ * the plan tree that would let us figure out what it had
+ * originally referenced. In that case, fall back on
+ * printing "fN", analogously to the default column names
+ * for RowExprs.
*/
TargetEntry *tle;
deparse_namespace save_dpns;
const char *result;
if (!dpns->inner_planstate)
- elog(ERROR, "failed to find plan for subquery %s",
- rte->eref->aliasname);
+ {
+ char *dummy_name = palloc(32);
+
+ snprintf(dummy_name, 32, "f%d", fieldno);
+ return dummy_name;
+ }
+
tle = get_tle_by_resno(dpns->inner_tlist, attnum);
if (!tle)
elog(ERROR, "bogus varattno for subquery var: %d",
@@ -7338,17 +7350,24 @@ get_name_for_var_field(Var *var, int fieldno,
{
/*
* We're deparsing a Plan tree so we don't have a CTE
- * list. But the only place we'd see a Var directly
- * referencing a CTE RTE is in a CteScan plan node, and we
- * can look into the subplan's tlist instead.
+ * list. But the only place we'd normally see a Var
+ * directly referencing a CTE RTE is in a CteScan plan
+ * node, and we can look into the subplan's tlist instead.
+ * As above, this can fail if the CTE has been proven
+ * empty, in which case fall back to "fN".
*/
TargetEntry *tle;
deparse_namespace save_dpns;
const char *result;
if (!dpns->inner_planstate)
- elog(ERROR, "failed to find plan for CTE %s",
- rte->eref->aliasname);
+ {
+ char *dummy_name = palloc(32);
+
+ snprintf(dummy_name, 32, "f%d", fieldno);
+ return dummy_name;
+ }
+
tle = get_tle_by_resno(dpns->inner_tlist, attnum);
if (!tle)
elog(ERROR, "bogus varattno for subquery var: %d",
diff --git a/src/test/regress/expected/rowtypes.out b/src/test/regress/expected/rowtypes.out
index 17ce98c58cd..573bc7f00fa 100644
--- a/src/test/regress/expected/rowtypes.out
+++ b/src/test/regress/expected/rowtypes.out
@@ -1264,6 +1264,60 @@ select pg_get_viewdef('composite_v', true);
drop view composite_v;
--
+-- Check cases where the composite comes from a proven-dummy rel (bug #18576)
+--
+explain (verbose, costs off)
+select (ss.a).x, (ss.a).n from
+ (select information_schema._pg_expandarray(array[1,2]) AS a) ss;
+ QUERY PLAN
+------------------------------------------------------------------------
+ Subquery Scan on ss
+ Output: (ss.a).x, (ss.a).n
+ -> ProjectSet
+ Output: information_schema._pg_expandarray('{1,2}'::integer[])
+ -> Result
+(5 rows)
+
+explain (verbose, costs off)
+select (ss.a).x, (ss.a).n from
+ (select information_schema._pg_expandarray(array[1,2]) AS a) ss
+where false;
+ QUERY PLAN
+--------------------------
+ Result
+ Output: (a).f1, (a).f2
+ One-Time Filter: false
+(3 rows)
+
+explain (verbose, costs off)
+with cte(c) as materialized (select row(1, 2)),
+ cte2(c) as (select * from cte)
+select (c).f1 from cte2 as t;
+ QUERY PLAN
+-----------------------------------
+ CTE Scan on cte
+ Output: (cte.c).f1
+ CTE cte
+ -> Result
+ Output: '(1,2)'::record
+(5 rows)
+
+explain (verbose, costs off)
+with cte(c) as materialized (select row(1, 2)),
+ cte2(c) as (select * from cte)
+select (c).f1 from cte2 as t
+where false;
+ QUERY PLAN
+-----------------------------------
+ Result
+ Output: (cte.c).f1
+ One-Time Filter: false
+ CTE cte
+ -> Result
+ Output: '(1,2)'::record
+(6 rows)
+
+--
-- Tests for component access / FieldSelect
--
CREATE TABLE compositetable(a text, b text);
diff --git a/src/test/regress/sql/rowtypes.sql b/src/test/regress/sql/rowtypes.sql
index 72c9df0d7d8..9770681b80d 100644
--- a/src/test/regress/sql/rowtypes.sql
+++ b/src/test/regress/sql/rowtypes.sql
@@ -510,6 +510,27 @@ select pg_get_viewdef('composite_v', true);
drop view composite_v;
--
+-- Check cases where the composite comes from a proven-dummy rel (bug #18576)
+--
+explain (verbose, costs off)
+select (ss.a).x, (ss.a).n from
+ (select information_schema._pg_expandarray(array[1,2]) AS a) ss;
+explain (verbose, costs off)
+select (ss.a).x, (ss.a).n from
+ (select information_schema._pg_expandarray(array[1,2]) AS a) ss
+where false;
+
+explain (verbose, costs off)
+with cte(c) as materialized (select row(1, 2)),
+ cte2(c) as (select * from cte)
+select (c).f1 from cte2 as t;
+explain (verbose, costs off)
+with cte(c) as materialized (select row(1, 2)),
+ cte2(c) as (select * from cte)
+select (c).f1 from cte2 as t
+where false;
+
+--
-- Tests for component access / FieldSelect
--
CREATE TABLE compositetable(a text, b text);
generated by cgit v1.2.3 (git 2.46.0) at 2025-09-13 04:42:06 +0000