diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 1363b9bd45..4fd8a77f48 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -1833,9 +1833,6 @@ cost_incremental_sort(Path *path,
 
 	Assert(presorted_keys != 0);
 
-	if (!enable_sort)
-		startup_cost += disable_cost;
-
 	if (!enable_incrementalsort)
 		startup_cost += disable_cost;
 
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index 704cfd032d..f920fbff30 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -762,6 +762,15 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 	/* Relation should be OK for parallelism, too. */
 	Assert(parent_rel->consider_parallel);
 
+	if (IsA(new_path, AggPath))
+	{
+		AggPath *path = (AggPath *) new_path;
+		/* we only care about first step of partial aggregates here */
+		if (path->aggsplit == AGGSPLIT_INITIAL_SERIAL)
+			elog(WARNING, "rel %p adding partial agg path %p startup %f total %f", 
+				 parent_rel, path, new_path->startup_cost, new_path->total_cost);
+	}
+
 	/*
 	 * As in add_path, throw out any paths which are dominated by the new
 	 * path, but throw out the new path if some existing path dominates it.
@@ -782,7 +791,10 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 			{
 				/* New path costs more; keep it only if pathkeys are better. */
 				if (keyscmp != PATHKEYS_BETTER1)
+				{
+					elog(WARNING, "A: new path %p rejected because of %p", new_path, old_path);
 					accept_new = false;
+				}
 			}
 			else if (old_path->total_cost > new_path->total_cost
 					 * STD_FUZZ_FACTOR)
@@ -799,6 +811,7 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 			else if (keyscmp == PATHKEYS_BETTER2)
 			{
 				/* Costs are about the same, old path has better pathkeys. */
+				elog(WARNING, "B: new path %p rejected because of %p", new_path, old_path);
 				accept_new = false;
 			}
 			else if (old_path->total_cost > new_path->total_cost * 1.0000000001)
@@ -813,6 +826,7 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 				 * cheaper.
 				 */
 				accept_new = false;
+				elog(WARNING, "C: new path %p rejected because of %p", new_path, old_path);
 			}
 		}
 
@@ -841,6 +855,8 @@ add_partial_path(RelOptInfo *parent_rel, Path *new_path)
 			break;
 	}
 
+	elog(WARNING, "rel %p path %p adding new = %d", parent_rel, new_path, accept_new);
+
 	if (accept_new)
 	{
 		/* Accept the new path: insert it at proper place */