From: Robert Haas <rhaas@postgresql.org>
Date: Tue, 15 Jul 2025 16:40:31 +0000 (-0400)
Subject: add query features earlier before considering elided nodes
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=62e4d8381ac469fbcc0b64e0748f025d852c7479;p=users%2Frhaas%2Fpostgres.git

add query features earlier before considering elided nodes
---

diff --git a/contrib/pg_plan_advice/pgpa_walker.c b/contrib/pg_plan_advice/pgpa_walker.c
index 694961eac8..3d8bd752af 100644
--- a/contrib/pg_plan_advice/pgpa_walker.c
+++ b/contrib/pg_plan_advice/pgpa_walker.c
@@ -35,33 +35,61 @@ pgpa_plan_walker(pgpa_plan_walker_context *context, Plan *plan,
 	bool		is_query_feature = false;
 
 	/*
-	 * Find all elided nodes for this Plan node.
+	 * If this is a Gather or Gather Merge node, directly add it to the list
+	 * of currently-active query features.
 	 *
-	 * Also, because query features are specific to a subquery level, we reset
-	 * the active_query_features list if this node has an elided SubqueryScan.
+	 * Otherwise, check the future_query_features list to see whether this
+	 * was previously identified as a plan node that needs to be treated as
+	 * a query feature.
+	 */
+	if (IsA(plan, Gather))
+	{
+		active_query_features =
+			lappend(active_query_features,
+					pgpa_add_feature(context, PGPAQF_GATHER, plan));
+		is_query_feature = true;
+	}
+	else if (IsA(plan, GatherMerge))
+	{
+		active_query_features =
+			lappend(active_query_features,
+					pgpa_add_feature(context, PGPAQF_GATHER_MERGE, plan));
+		is_query_feature = true;
+	}
+	else
+	{
+		foreach_ptr(pgpa_query_feature, qf, context->future_query_features)
+		{
+			if (qf->plan == plan)
+			{
+				is_query_feature = true;
+				active_query_features = lappend(active_query_features, qf);
+				context->future_query_features =
+					list_delete_ptr(context->future_query_features, plan);
+				break;
+			}
+		}
+	}
+
+	/*
+	 * Find all elided nodes for this Plan node.
 	 */
 	foreach_node(ElidedNode, n, context->pstmt->elidedNodes)
 	{
 		if (n->plan_node_id == plan->plan_node_id)
-		{
 			elided_nodes = lappend(elided_nodes, n);
-			if (n->elided_type == T_SubqueryScan)
-				active_query_features = NIL;
-		}
 	}
 
 	/* If we found any elided_nodes, handle them. */
 	if (elided_nodes != NIL)
 	{
 		int			num_elided_nodes = list_length(elided_nodes);
+		ElidedNode *last_elided_node;
 
 		/* XXX */
-		{
-			ElidedNode *last_elided_node;
-
-			last_elided_node = list_nth(elided_nodes, num_elided_nodes - 1);
-			pgpa_qf_add_rtis(active_query_features, last_elided_node->relids);
-		}
+		last_elided_node = list_nth(elided_nodes, num_elided_nodes - 1);
+		pgpa_qf_add_rtis(active_query_features, last_elided_node->relids);
+		active_query_features = NIL;
 
 		/*
 		 * If there are multiple relids for the elided node, a clumped join
@@ -141,43 +169,6 @@ pgpa_plan_walker(pgpa_plan_walker_context *context, Plan *plan,
 		pgpa_unroll_join(context, plan, join_unroller,
 						 &outer_join_unroller, &inner_join_unroller);
 
-	/*
-	 * If this is a Gather or Gather Merge node, directly add it to the list
-	 * of currently-active query features.
-	 *
-	 * Otherwise, check the future_query_features list to see whether this
-	 * was previously identified as a plan node that needs to be treated as
-	 * a query feature.
-	 */
-	if (IsA(plan, Gather))
-	{
-		active_query_features =
-			lappend(active_query_features,
-					pgpa_add_feature(context, PGPAQF_GATHER, plan));
-		is_query_feature = true;
-	}
-	else if (IsA(plan, GatherMerge))
-	{
-		active_query_features =
-			lappend(active_query_features,
-					pgpa_add_feature(context, PGPAQF_GATHER_MERGE, plan));
-		is_query_feature = true;
-	}
-	else
-	{
-		foreach_ptr(pgpa_query_feature, qf, context->future_query_features)
-		{
-			if (qf->plan == plan)
-			{
-				is_query_feature = true;
-				active_query_features = lappend(active_query_features, qf);
-				context->future_query_features =
-					list_delete_ptr(context->future_query_features, plan);
-				break;
-			}
-		}
-	}
-
 	/* Add RTIs from the plan node to all active query features. */
 	pgpa_qf_add_plan_rtis(active_query_features, plan);