v2-0001-fix-expand-virtual-generated-column-Var-node-varn.patch

From 2f9bd9ec737227b1b2dc52a4800d006bfa228003 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Thu, 13 Feb 2025 11:28:57 +0800
Subject: [PATCH v2 1/1] fix expand virtual generated column Var node
 varnullingrels field

To expand the virtual generated column Var node,
we need to copy the fields of the original virtual generated column Var node,
including varnullingrels, varlevelsup, varreturningtype, and varattno,
to the newly expanded Var node.

ReplaceVarsFromTargetList_callback didn't taken care of varnullingrels,
this patch fix this issue.

discussion: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
---
 src/backend/rewrite/rewriteManip.c            | 62 +++++++++++++++++++
 src/include/rewrite/rewriteManip.h            |  3 +
 .../regress/expected/generated_virtual.out    | 45 ++++++++++++++
 src/test/regress/sql/generated_virtual.sql    | 11 ++++
 src/tools/pgindent/typedefs.list              |  1 +
 5 files changed, 122 insertions(+)

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index a115b217c91..69701ce6ecd 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -884,6 +884,64 @@ IncrementVarSublevelsUp_rtable(List *rtable, int delta_sublevels_up,
 					   QTW_EXAMINE_RTES_BEFORE);
 }
 
+/*
+ * SetVarNullingrels - adjust Var nodes for a specified varnullingrels.
+ *
+ * Find all Var nodes referring to the specified varno in the given
+ * expression and set their varnullingrels to the specified value.
+ */
+typedef struct
+{
+	int			sublevels_up;
+	int			varno;
+	Bitmapset *varnullingrels;
+} SetVarNullingrels_context;
+
+static bool
+SetVarNullingrels_walker(Node *node,
+						 SetVarNullingrels_context *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) node;
+
+		if (var->varlevelsup == context->sublevels_up &&
+			var->varno == context->varno)
+			var->varnullingrels = bms_union(context->varnullingrels,
+											var->varnullingrels);
+
+		return false;
+	}
+
+	if (IsA(node, Query))
+	{
+		/* Recurse into subselects */
+		bool		result;
+
+		context->sublevels_up++;
+		result = query_tree_walker((Query *) node, SetVarNullingrels_walker,
+								   context, 0);
+		context->sublevels_up--;
+		return result;
+	}
+	return expression_tree_walker(node, SetVarNullingrels_walker, context);
+}
+void
+SetVarNullingrels(Node *node, int sublevels_up, int varno, Bitmapset *varnullingrels)
+{
+	SetVarNullingrels_context context;
+
+	context.sublevels_up = sublevels_up;
+	context.varno = varno;
+	context.varnullingrels = varnullingrels;
+
+	/* Expect to start with an expression */
+	SetVarNullingrels_walker(node, &context);
+}
+
 /*
  * SetVarReturningType - adjust Var nodes for a specified varreturningtype.
  *
@@ -1832,6 +1890,10 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		if (var->varlevelsup > 0)
 			IncrementVarSublevelsUp((Node *) newnode, var->varlevelsup, 0);
 
+		if (var->varnullingrels != NULL)
+			SetVarNullingrels((Node *) newnode, var->varlevelsup,
+							  var->varno,
+							  var->varnullingrels);
 		/*
 		 * Check to see if the tlist item contains a PARAM_MULTIEXPR Param,
 		 * and throw error if so.  This case could only happen when expanding
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 512823033b9..e869f651fc8 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -48,6 +48,9 @@ extern void ChangeVarNodes(Node *node, int rt_index, int new_index,
 						   int sublevels_up);
 extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 									int min_sublevels_up);
+extern void SetVarNullingrels(Node *node, int sublevels_up,
+							  int varno,
+							  Bitmapset *varnullingrels);
 extern void IncrementVarSublevelsUp_rtable(List *rtable,
 										   int delta_sublevels_up, int min_sublevels_up);
 
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 35638812be9..56e7e6fd6b0 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -181,6 +181,51 @@ SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
  22 | 2 | 2 | 4
 (2 rows)
 
+--bug: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
+SELECT SUM(t.b) OVER (PARTITION BY t.a) FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+  12
+  12
+  12
+(6 rows)
+
+--this query result should be same as as the above
+SELECT SUM((select t.b from ((select t.b from gtest1 as t order by t.b limit 1)))) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+  12
+  12
+  12
+(6 rows)
+
+SELECT SUM((select t.b from gtest1 as t order by t.b limit 1)) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+   6
+   6
+   6
+(6 rows)
+
+SELECT t.x FROM gtestx t LEFT JOIN gtest1 vt on t.x = vt.a WHERE coalesce(vt.b, 1) = 1 OR t.x IS NULL;
+ x  
+----
+ 11
+ 22
+ 33
+(3 rows)
+
 DROP TABLE gtestx;
 -- test UPDATE/DELETE quals
 SELECT * FROM gtest1 ORDER BY a;
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index 34870813910..d76439ca993 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -80,6 +80,17 @@ DELETE FROM gtest1 WHERE a = 2000000000;
 CREATE TABLE gtestx (x int, y int);
 INSERT INTO gtestx VALUES (11, 1), (22, 2), (33, 3);
 SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
+--bug: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
+SELECT SUM(t.b) OVER (PARTITION BY t.a) FROM gtestx AS t1 left JOIN gtest1 T ON true;
+--this query result should be same as as the above
+SELECT SUM((select t.b from ((select t.b from gtest1 as t order by t.b limit 1)))) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+
+SELECT SUM((select t.b from gtest1 as t order by t.b limit 1)) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+
+SELECT t.x FROM gtestx t LEFT JOIN gtest1 vt on t.x = vt.a WHERE coalesce(vt.b, 1) = 1 OR t.x IS NULL;
+
 DROP TABLE gtestx;
 
 -- test UPDATE/DELETE quals
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b6c170ac249..6cb39ac76c5 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2633,6 +2633,7 @@ SetOperation
 SetOperationStmt
 SetQuantifier
 SetToDefault
+SetVarNullingrels_context
 SetVarReturningType_context
 SetupWorkerPtrType
 ShDependObjectInfo
-- 
2.34.1