Add bms_next_member(), and use it where appropriate.

This patch adds a way of iterating through the members of a bitmapset
nondestructively, unlike the old way with bms_first_member().  While
bms_next_member() is very slightly slower than bms_first_member()
(at least for typical-size bitmapsets), eliminating the need to palloc
and pfree a temporary copy of the target bitmapset is a significant win.
So this method should be preferred in all cases where a temporary copy
would be necessary.

Tom Lane, with suggestions from Dean Rasheed and David Rowley

1 files changed, 2 insertions, 4 deletions

diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 25f30676f0..449fdc3474 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -2272,19 +2272,17 @@ remove_unused_subquery_outputs(Query *subquery, RelOptInfo *rel)
 static void
 print_relids(Relids relids)
 {
-	Relids		tmprelids;
 	int			x;
 	bool		first = true;
 
-	tmprelids = bms_copy(relids);
-	while ((x = bms_first_member(tmprelids)) >= 0)
+	x = -1;
+	while ((x = bms_next_member(relids, x)) >= 0)
 	{
 		if (!first)
 			printf(" ");
 		printf("%d", x);
 		first = false;
 	}
-	bms_free(tmprelids);
 }
 
 static void