1 files changed, 108 insertions, 30 deletions

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index cd786aa4112..3f8b8b6eed9 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -550,15 +550,19 @@ offset_relid_set(Relids relids, int offset)
  * earlier to ensure that no unwanted side-effects occur!
  */
 
+typedef struct
+{
+	int			rt_index;
+	int			new_index;
+	int			sublevels_up;
+	bool		change_RangeTblRef;
+} ChangeVarNodes_context;
+
 static bool
 ChangeVarNodes_walker(Node *node, ChangeVarNodes_context *context)
 {
 	if (node == NULL)
 		return false;
-
-	if (context->callback && context->callback(node, context))
-		return false;
-
 	if (IsA(node, Var))
 	{
 		Var		   *var = (Var *) node;
@@ -584,7 +588,7 @@ ChangeVarNodes_walker(Node *node, ChangeVarNodes_context *context)
 			cexpr->cvarno = context->new_index;
 		return false;
 	}
-	if (IsA(node, RangeTblRef))
+	if (IsA(node, RangeTblRef) && context->change_RangeTblRef)
 	{
 		RangeTblRef *rtr = (RangeTblRef *) node;
 
@@ -631,6 +635,95 @@ ChangeVarNodes_walker(Node *node, ChangeVarNodes_context *context)
 		}
 		return false;
 	}
+	if (IsA(node, RestrictInfo))
+	{
+		RestrictInfo *rinfo = (RestrictInfo *) node;
+		int			relid = -1;
+		bool		is_req_equal =
+			(rinfo->required_relids == rinfo->clause_relids);
+		bool		clause_relids_is_multiple =
+			(bms_membership(rinfo->clause_relids) == BMS_MULTIPLE);
+
+		/*
+		 * Recurse down into clauses if the target relation is present in
+		 * clause_relids or required_relids.  We must check required_relids
+		 * because the relation not present in clause_relids might still be
+		 * present somewhere in orclause.
+		 */
+		if (bms_is_member(context->rt_index, rinfo->clause_relids) ||
+			bms_is_member(context->rt_index, rinfo->required_relids))
+		{
+			Relids		new_clause_relids;
+
+			expression_tree_walker((Node *) rinfo->clause, ChangeVarNodes_walker, (void *) context);
+			expression_tree_walker((Node *) rinfo->orclause, ChangeVarNodes_walker, (void *) context);
+
+			new_clause_relids = adjust_relid_set(rinfo->clause_relids,
+												 context->rt_index,
+												 context->new_index);
+
+			/*
+			 * Incrementally adjust num_base_rels based on the change of
+			 * clause_relids, which could contain both base relids and
+			 * outer-join relids.  This operation is legal until we remove
+			 * only baserels.
+			 */
+			rinfo->num_base_rels -= bms_num_members(rinfo->clause_relids) -
+				bms_num_members(new_clause_relids);
+
+			rinfo->clause_relids = new_clause_relids;
+			rinfo->left_relids =
+				adjust_relid_set(rinfo->left_relids, context->rt_index, context->new_index);
+			rinfo->right_relids =
+				adjust_relid_set(rinfo->right_relids, context->rt_index, context->new_index);
+		}
+
+		if (is_req_equal)
+			rinfo->required_relids = rinfo->clause_relids;
+		else
+			rinfo->required_relids =
+				adjust_relid_set(rinfo->required_relids, context->rt_index, context->new_index);
+
+		rinfo->outer_relids =
+			adjust_relid_set(rinfo->outer_relids, context->rt_index, context->new_index);
+		rinfo->incompatible_relids =
+			adjust_relid_set(rinfo->incompatible_relids, context->rt_index, context->new_index);
+
+		if (rinfo->mergeopfamilies &&
+			bms_get_singleton_member(rinfo->clause_relids, &relid) &&
+			clause_relids_is_multiple &&
+			relid == context->new_index && IsA(rinfo->clause, OpExpr))
+		{
+			Expr	   *leftOp;
+			Expr	   *rightOp;
+
+			leftOp = (Expr *) get_leftop(rinfo->clause);
+			rightOp = (Expr *) get_rightop(rinfo->clause);
+
+			/*
+			 * For self-join elimination, changing varnos could transform
+			 * "t1.a = t2.a" into "t1.a = t1.a".  That is always true as long
+			 * as "t1.a" is not null.  We use qual() to check for such a case,
+			 * and then we replace the qual for a check for not null
+			 * (NullTest).
+			 */
+			if (leftOp != NULL && equal(leftOp, rightOp))
+			{
+				NullTest   *ntest = makeNode(NullTest);
+
+				ntest->arg = leftOp;
+				ntest->nulltesttype = IS_NOT_NULL;
+				ntest->argisrow = false;
+				ntest->location = -1;
+				rinfo->clause = (Expr *) ntest;
+				rinfo->mergeopfamilies = NIL;
+				rinfo->left_em = NULL;
+				rinfo->right_em = NULL;
+			}
+			Assert(rinfo->orclause == NULL);
+		}
+		return false;
+	}
 	if (IsA(node, AppendRelInfo))
 	{
 		AppendRelInfo *appinfo = (AppendRelInfo *) node;
@@ -664,28 +757,26 @@ ChangeVarNodes_walker(Node *node, ChangeVarNodes_context *context)
 }
 
 /*
- * ChangeVarNodesExtended - similar to ChangeVarNodes, but with an  additional
- *							'callback' param
+ * ChangeVarNodesExtended - similar to ChangeVarNodes, but has additional
+ *							'change_RangeTblRef' param
  *
  * ChangeVarNodes changes a given node and all of its underlying nodes.
- * This version of function additionally takes a callback, which has a
- * chance to process a node before ChangeVarNodes_walker.  A callback
- * returns a boolean value indicating if given node should be skipped from
- * further processing by ChangeVarNodes_walker.  The callback is called
- * only for expressions and other children nodes of a Query processed by
- * a walker.  Initial processing of the root Query doesn't involve the
- * callback.
+ * However, self-join elimination (SJE) needs to skip the RangeTblRef node
+ * type.  During SJE's last step, remove_rel_from_joinlist() removes
+ * remaining RangeTblRefs with target relid.  If ChangeVarNodes() replaces
+ * the target relid before, remove_rel_from_joinlist() fails to identify
+ * the nodes to delete.
  */
 void
 ChangeVarNodesExtended(Node *node, int rt_index, int new_index,
-					   int sublevels_up, ChangeVarNodes_callback callback)
+					   int sublevels_up, bool change_RangeTblRef)
 {
 	ChangeVarNodes_context context;
 
 	context.rt_index = rt_index;
 	context.new_index = new_index;
 	context.sublevels_up = sublevels_up;
-	context.callback = callback;
+	context.change_RangeTblRef = change_RangeTblRef;
 
 	/*
 	 * Must be prepared to start with a Query or a bare expression tree; if
@@ -735,20 +826,7 @@ ChangeVarNodesExtended(Node *node, int rt_index, int new_index,
 void
 ChangeVarNodes(Node *node, int rt_index, int new_index, int sublevels_up)
 {
-	ChangeVarNodesExtended(node, rt_index, new_index, sublevels_up, NULL);
-}
-
-/*
- * ChangeVarNodesWalkExpression - process expression within the custom
- *								  callback provided to the
- *								  ChangeVarNodesExtended.
- */
-bool
-ChangeVarNodesWalkExpression(Node *node, ChangeVarNodes_context *context)
-{
-	return expression_tree_walker(node,
-								  ChangeVarNodes_walker,
-								  (void *) context);
+	ChangeVarNodesExtended(node, rt_index, new_index, sublevels_up, true);
 }
 
 /*