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-rw-r--r--src/backend/optimizer/path/allpaths.c50
-rw-r--r--src/backend/parser/parse_clause.c1
-rw-r--r--src/test/regress/expected/window.out19
-rw-r--r--src/test/regress/sql/window.sql10
4 files changed, 69 insertions, 11 deletions
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 7ac116a791f..e9342097e52 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -142,7 +142,8 @@ static void subquery_push_qual(Query *subquery,
RangeTblEntry *rte, Index rti, Node *qual);
static void recurse_push_qual(Node *setOp, Query *topquery,
RangeTblEntry *rte, Index rti, Node *qual);
-static void remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel);
+static void remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel,
+ Bitmapset *extra_used_attrs);
/*
@@ -2177,14 +2178,16 @@ has_multiple_baserels(PlannerInfo *root)
* the run condition will handle all of the required filtering.
*
* Returns true if 'opexpr' was found to be useful and was added to the
- * WindowClauses runCondition. We also set *keep_original accordingly.
+ * WindowClauses runCondition. We also set *keep_original accordingly and add
+ * 'attno' to *run_cond_attrs offset by FirstLowInvalidHeapAttributeNumber.
* If the 'opexpr' cannot be used then we set *keep_original to true and
* return false.
*/
static bool
find_window_run_conditions(Query *subquery, RangeTblEntry *rte, Index rti,
AttrNumber attno, WindowFunc *wfunc, OpExpr *opexpr,
- bool wfunc_left, bool *keep_original)
+ bool wfunc_left, bool *keep_original,
+ Bitmapset **run_cond_attrs)
{
Oid prosupport;
Expr *otherexpr;
@@ -2356,6 +2359,9 @@ find_window_run_conditions(Query *subquery, RangeTblEntry *rte, Index rti,
wclause->runCondition = lappend(wclause->runCondition, newexpr);
+ /* record that this attno was used in a run condition */
+ *run_cond_attrs = bms_add_member(*run_cond_attrs,
+ attno - FirstLowInvalidHeapAttributeNumber);
return true;
}
@@ -2369,13 +2375,17 @@ find_window_run_conditions(Query *subquery, RangeTblEntry *rte, Index rti,
* WindowClause as a 'runCondition' qual. These, when present, allow
* some unnecessary work to be skipped during execution.
*
+ * 'run_cond_attrs' will be populated with all targetlist resnos of subquery
+ * targets (offset by FirstLowInvalidHeapAttributeNumber) that we pushed
+ * window quals for.
+ *
* Returns true if the caller still must keep the original qual or false if
* the caller can safely ignore the original qual because the WindowAgg node
* will use the runCondition to stop returning tuples.
*/
static bool
check_and_push_window_quals(Query *subquery, RangeTblEntry *rte, Index rti,
- Node *clause)
+ Node *clause, Bitmapset **run_cond_attrs)
{
OpExpr *opexpr = (OpExpr *) clause;
bool keep_original = true;
@@ -2403,7 +2413,8 @@ check_and_push_window_quals(Query *subquery, RangeTblEntry *rte, Index rti,
WindowFunc *wfunc = (WindowFunc *) tle->expr;
if (find_window_run_conditions(subquery, rte, rti, tle->resno, wfunc,
- opexpr, true, &keep_original))
+ opexpr, true, &keep_original,
+ run_cond_attrs))
return keep_original;
}
@@ -2415,7 +2426,8 @@ check_and_push_window_quals(Query *subquery, RangeTblEntry *rte, Index rti,
WindowFunc *wfunc = (WindowFunc *) tle->expr;
if (find_window_run_conditions(subquery, rte, rti, tle->resno, wfunc,
- opexpr, false, &keep_original))
+ opexpr, false, &keep_original,
+ run_cond_attrs))
return keep_original;
}
@@ -2444,6 +2456,7 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
pushdown_safety_info safetyInfo;
double tuple_fraction;
RelOptInfo *sub_final_rel;
+ Bitmapset *run_cond_attrs = NULL;
ListCell *lc;
/*
@@ -2526,7 +2539,8 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
* it might be useful to use for the WindowAgg's runCondition.
*/
if (!subquery->hasWindowFuncs ||
- check_and_push_window_quals(subquery, rte, rti, clause))
+ check_and_push_window_quals(subquery, rte, rti, clause,
+ &run_cond_attrs))
{
/*
* subquery has no window funcs or the clause is not a
@@ -2545,9 +2559,11 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
/*
* The upper query might not use all the subquery's output columns; if
- * not, we can simplify.
+ * not, we can simplify. Pass the attributes that were pushed down into
+ * WindowAgg run conditions to ensure we don't accidentally think those
+ * are unused.
*/
- remove_unused_subquery_outputs(subquery, rel);
+ remove_unused_subquery_outputs(subquery, rel, run_cond_attrs);
/*
* We can safely pass the outer tuple_fraction down to the subquery if the
@@ -3945,17 +3961,29 @@ recurse_push_qual(Node *setOp, Query *topquery,
* compute expressions, but because deletion of output columns might allow
* optimizations such as join removal to occur within the subquery.
*
+ * extra_used_attrs can be passed as non-NULL to mark any columns (offset by
+ * FirstLowInvalidHeapAttributeNumber) that we should not remove. This
+ * parameter is modifed by the function, so callers must make a copy if they
+ * need to use the passed in Bitmapset after calling this function.
+ *
* To avoid affecting column numbering in the targetlist, we don't physically
* remove unused tlist entries, but rather replace their expressions with NULL
* constants. This is implemented by modifying subquery->targetList.
*/
static void
-remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel)
+remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel,
+ Bitmapset *extra_used_attrs)
{
- Bitmapset *attrs_used = NULL;
+ Bitmapset *attrs_used;
ListCell *lc;
/*
+ * Just point directly to extra_used_attrs. No need to bms_copy as none of
+ * the current callers use the Bitmapset after calling this function.
+ */
+ attrs_used = extra_used_attrs;
+
+ /*
* Do nothing if subquery has UNION/INTERSECT/EXCEPT: in principle we
* could update all the child SELECTs' tlists, but it seems not worth the
* trouble presently.
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 249255b65f5..c655d188c76 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -2831,6 +2831,7 @@ transformWindowDefinitions(ParseState *pstate,
rangeopfamily, rangeopcintype,
&wc->endInRangeFunc,
windef->endOffset);
+ wc->runCondition = NIL;
wc->winref = winref;
result = lappend(result, wc);
diff --git a/src/test/regress/expected/window.out b/src/test/regress/expected/window.out
index d78b4c463cf..433a0bb0259 100644
--- a/src/test/regress/expected/window.out
+++ b/src/test/regress/expected/window.out
@@ -3589,6 +3589,25 @@ WHERE rn < 3;
3 | sales | 2
(6 rows)
+-- ensure that "unused" subquery columns are not removed when the column only
+-- exists in the run condition
+EXPLAIN (COSTS OFF)
+SELECT empno, depname FROM
+ (SELECT empno,
+ depname,
+ row_number() OVER (PARTITION BY depname ORDER BY empno) rn
+ FROM empsalary) emp
+WHERE rn < 3;
+ QUERY PLAN
+------------------------------------------------------------
+ Subquery Scan on emp
+ -> WindowAgg
+ Run Condition: (row_number() OVER (?) < 3)
+ -> Sort
+ Sort Key: empsalary.depname, empsalary.empno
+ -> Seq Scan on empsalary
+(6 rows)
+
-- likewise with count(empno) instead of row_number()
EXPLAIN (COSTS OFF)
SELECT * FROM
diff --git a/src/test/regress/sql/window.sql b/src/test/regress/sql/window.sql
index 967b9413de6..a504e46e403 100644
--- a/src/test/regress/sql/window.sql
+++ b/src/test/regress/sql/window.sql
@@ -1121,6 +1121,16 @@ SELECT * FROM
FROM empsalary) emp
WHERE rn < 3;
+-- ensure that "unused" subquery columns are not removed when the column only
+-- exists in the run condition
+EXPLAIN (COSTS OFF)
+SELECT empno, depname FROM
+ (SELECT empno,
+ depname,
+ row_number() OVER (PARTITION BY depname ORDER BY empno) rn
+ FROM empsalary) emp
+WHERE rn < 3;
+
-- likewise with count(empno) instead of row_number()
EXPLAIN (COSTS OFF)
SELECT * FROM
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-30 00:17:11 +0000