diff --git a/db/Experiment.pm.in b/db/Experiment.pm.in
index 526674eab7b998aa064757fa12a3854587e42f41..25d87616a75d2c8e8a539bbb5bd04130137b0e74 100644
--- a/db/Experiment.pm.in
+++ b/db/Experiment.pm.in
@@ -103,7 +103,7 @@ my $EXPT_RESOURCESHOSED = 0;
 		   "ipport_ranges" => undef,
 		   "v2pmap"        => ["node_id", "vname"],
 		   "linkdelays"    => ["node_id", "vlan", "vnode"],
-		   "traces"        => ["idx"],
+		   "traces"        => ["node_id", "idx"],
 		   "portmap"       => undef); 
 
 # These are slots in the node table that need to be restored. 
@@ -3124,7 +3124,9 @@ sub BackupPhysicalState($;$$)
     if (@pnodenames) {
 	my $clause = join(" or ", map("node_id='$_'", @pnodenames));
 
+	# This ordering is for wrapper/mapper regression testing. 
 	DBQueryWarn("select * from nodes where $clause ".
+		    "order by node_id ".
 		    "into outfile '$pstateDir/nodes' ")
 	    or $errors++;
 	# This ordering is for wrapper/mapper regression testing.