>>>>> "Tom" == Tom Lane <t...@sss.pgh.pa.us> writes:
>> I'm going to leave the assertion out for now and put in a comment
>> for future reference.
Tom> WFM. At this point it's clear it would be a separate piece of work
Tom> not something to slide into the bug-fix patch, anyway.
OK. So here's the final patch.
(For the benefit of anyone in -hackers not following the original thread
in -general, the problem here is that expressions in window framing
clauses were not being walked or mutated by query_tree_walker /
query_tree_mutator. This has been wrong ever since 9.0, but somehow
nobody seems to have noticed until now.)
--
Andrew (irc:RhodiumToad)
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index dd0a7d8dac..03582781f6 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -2214,18 +2214,13 @@ find_expr_references_walker(Node *node,
context->addrs);
}
- /* query_tree_walker ignores ORDER BY etc, but we need those opers */
- find_expr_references_walker((Node *) query->sortClause, context);
- find_expr_references_walker((Node *) query->groupClause, context);
- find_expr_references_walker((Node *) query->windowClause, context);
- find_expr_references_walker((Node *) query->distinctClause, context);
-
/* Examine substructure of query */
context->rtables = lcons(query->rtable, context->rtables);
result = query_tree_walker(query,
find_expr_references_walker,
(void *) context,
- QTW_IGNORE_JOINALIASES);
+ QTW_IGNORE_JOINALIASES |
+ QTW_EXAMINE_SORTGROUP);
context->rtables = list_delete_first(context->rtables);
return result;
}
diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
index 18bd5ac903..95051629e2 100644
--- a/src/backend/nodes/nodeFuncs.c
+++ b/src/backend/nodes/nodeFuncs.c
@@ -2278,6 +2278,13 @@ query_tree_walker(Query *query,
{
Assert(query != NULL && IsA(query, Query));
+ /*
+ * We don't walk any utilityStmt here. However, we can't easily assert
+ * that it is absent, since there are at least two code paths by which
+ * action statements from CREATE RULE end up here, and NOTIFY is allowed
+ * in a rule action.
+ */
+
if (walker((Node *) query->targetList, context))
return true;
if (walker((Node *) query->withCheckOptions, context))
@@ -2296,6 +2303,49 @@ query_tree_walker(Query *query,
return true;
if (walker(query->limitCount, context))
return true;
+ /*
+ * Most callers aren't interested in SortGroupClause nodes since those
+ * don't contain actual expressions. However they do contain OIDs which
+ * may be needed by dependency walkers etc.
+ */
+ if ((flags & QTW_EXAMINE_SORTGROUP))
+ {
+ if (walker((Node *) query->groupClause, context))
+ return true;
+ if (walker((Node *) query->windowClause, context))
+ return true;
+ if (walker((Node *) query->sortClause, context))
+ return true;
+ if (walker((Node *) query->distinctClause, context))
+ return true;
+ }
+ else
+ {
+ /*
+ * But we need to walk the expressions under WindowClause nodes even
+ * if we're not interested in SortGroupClause nodes.
+ */
+ ListCell *lc;
+ foreach(lc, query->windowClause)
+ {
+ WindowClause *wc = lfirst_node(WindowClause, lc);
+ if (walker(wc->startOffset, context))
+ return true;
+ if (walker(wc->endOffset, context))
+ return true;
+ }
+ }
+ /*
+ * groupingSets and rowMarks are not walked:
+ *
+ * groupingSets contain only ressortgrouprefs (integers) which are
+ * meaningless without the corresponding groupClause or tlist.
+ * Accordingly, any walker that needs to care about them needs to handle
+ * them itself in its Query processing.
+ *
+ * rowMarks is not walked because it contains only rangetable indexes (and
+ * flags etc.) and therefore should be handled at Query level similarly.
+ */
if (!(flags & QTW_IGNORE_CTE_SUBQUERIES))
{
if (walker((Node *) query->cteList, context))
@@ -3153,6 +3203,56 @@ query_tree_mutator(Query *query,
MUTATE(query->havingQual, query->havingQual, Node *);
MUTATE(query->limitOffset, query->limitOffset, Node *);
MUTATE(query->limitCount, query->limitCount, Node *);
+
+ /*
+ * Most callers aren't interested in SortGroupClause nodes since those
+ * don't contain actual expressions. However they do contain OIDs, which
+ * may be of interest to some mutators.
+ */
+
+ if ((flags & QTW_EXAMINE_SORTGROUP))
+ {
+ MUTATE(query->groupClause, query->groupClause, List *);
+ MUTATE(query->windowClause, query->windowClause, List *);
+ MUTATE(query->sortClause, query->sortClause, List *);
+ MUTATE(query->distinctClause, query->distinctClause, List *);
+ }
+ else
+ {
+ /*
+ * But we need to mutate the expressions under WindowClause nodes even
+ * if we're not interested in SortGroupClause nodes.
+ */
+ List *resultlist;
+ ListCell *temp;
+
+ resultlist = NIL;
+ foreach(temp, query->windowClause)
+ {
+ WindowClause *wc = lfirst_node(WindowClause, temp);
+ WindowClause *newnode;
+
+ FLATCOPY(newnode, wc, WindowClause);
+ MUTATE(newnode->startOffset, wc->startOffset, Node *);
+ MUTATE(newnode->endOffset, wc->endOffset, Node *);
+
+ resultlist = lappend(resultlist, (Node *) newnode);
+ }
+ query->windowClause = resultlist;
+ }
+
+ /*
+ * groupingSets and rowMarks are not mutated:
+ *
+ * groupingSets contain only ressortgroup refs (integers) which are
+ * meaningless without the groupClause or tlist. Accordingly, any mutator
+ * that needs to care about them needs to handle them itself in its Query
+ * processing.
+ *
+ * rowMarks contains only rangetable indexes (and flags etc.) and
+ * therefore should be handled at Query level similarly.
+ */
+
if (!(flags & QTW_IGNORE_CTE_SUBQUERIES))
MUTATE(query->cteList, query->cteList, List *);
else /* else copy CTE list as-is */
diff --git a/src/include/nodes/nodeFuncs.h b/src/include/nodes/nodeFuncs.h
index 0cb931c82c..4b5408fa9b 100644
--- a/src/include/nodes/nodeFuncs.h
+++ b/src/include/nodes/nodeFuncs.h
@@ -27,6 +27,7 @@
#define QTW_EXAMINE_RTES_AFTER 0x20 /* examine RTE nodes after their
* contents */
#define QTW_DONT_COPY_QUERY 0x40 /* do not copy top Query */
+#define QTW_EXAMINE_SORTGROUP 0x80 /* include SortGroupNode lists */
/* callback function for check_functions_in_node */
typedef bool (*check_function_callback) (Oid func_id, void *context);
diff --git a/src/test/regress/expected/window.out b/src/test/regress/expected/window.out
index edc93d5729..d5fd4045f9 100644
--- a/src/test/regress/expected/window.out
+++ b/src/test/regress/expected/window.out
@@ -3821,3 +3821,45 @@ SELECT i, b, bool_and(b) OVER w, bool_or(b) OVER w
5 | t | t | t
(5 rows)
+-- Tests for problems with failure to walk or mutate expressions
+-- within window frame clauses.
+-- test walker (fails with collation error if expressions are not walked)
+SELECT array_agg(i) OVER w
+ FROM generate_series(1,5) i
+WINDOW w AS (ORDER BY i ROWS BETWEEN (('foo' < 'foobar')::integer) PRECEDING AND CURRENT ROW);
+ array_agg
+-----------
+ {1}
+ {1,2}
+ {2,3}
+ {3,4}
+ {4,5}
+(5 rows)
+
+-- test mutator (fails when inlined if expressions are not mutated)
+CREATE FUNCTION pg_temp.f(group_size BIGINT) RETURNS SETOF integer[]
+AS $$
+ SELECT array_agg(s) OVER w
+ FROM generate_series(1,5) s
+ WINDOW w AS (ORDER BY s ROWS BETWEEN CURRENT ROW AND GROUP_SIZE FOLLOWING)
+$$ LANGUAGE SQL STABLE;
+EXPLAIN (costs off) SELECT * FROM pg_temp.f(2);
+ QUERY PLAN
+------------------------------------------------------
+ Subquery Scan on f
+ -> WindowAgg
+ -> Sort
+ Sort Key: s.s
+ -> Function Scan on generate_series s
+(5 rows)
+
+SELECT * FROM pg_temp.f(2);
+ f
+---------
+ {1,2,3}
+ {2,3,4}
+ {3,4,5}
+ {4,5}
+ {5}
+(5 rows)
+
diff --git a/src/test/regress/sql/window.sql b/src/test/regress/sql/window.sql
index fc6d4cc903..fe273aa31e 100644
--- a/src/test/regress/sql/window.sql
+++ b/src/test/regress/sql/window.sql
@@ -1257,3 +1257,22 @@ SELECT to_char(SUM(n::float8) OVER (ORDER BY i ROWS BETWEEN CURRENT ROW AND 1 FO
SELECT i, b, bool_and(b) OVER w, bool_or(b) OVER w
FROM (VALUES (1,true), (2,true), (3,false), (4,false), (5,true)) v(i,b)
WINDOW w AS (ORDER BY i ROWS BETWEEN CURRENT ROW AND 1 FOLLOWING);
+
+-- Tests for problems with failure to walk or mutate expressions
+-- within window frame clauses.
+
+-- test walker (fails with collation error if expressions are not walked)
+SELECT array_agg(i) OVER w
+ FROM generate_series(1,5) i
+WINDOW w AS (ORDER BY i ROWS BETWEEN (('foo' < 'foobar')::integer) PRECEDING AND CURRENT ROW);
+
+-- test mutator (fails when inlined if expressions are not mutated)
+CREATE FUNCTION pg_temp.f(group_size BIGINT) RETURNS SETOF integer[]
+AS $$
+ SELECT array_agg(s) OVER w
+ FROM generate_series(1,5) s
+ WINDOW w AS (ORDER BY s ROWS BETWEEN CURRENT ROW AND GROUP_SIZE FOLLOWING)
+$$ LANGUAGE SQL STABLE;
+
+EXPLAIN (costs off) SELECT * FROM pg_temp.f(2);
+SELECT * FROM pg_temp.f(2);
