diff --git a/src/backend/utils/mb/Unicode/UCS_to_most.pl b/src/backend/utils/mb/Unicode/UCS_to_most.pl
index 60431a6a27..1c3922e2ff 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_most.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_most.pl
@@ -50,7 +50,7 @@ my %filename = (
 	'GBK'        => 'CP936.TXT');
 
 # make maps for all encodings if not specified
-my @charsets = (scalar(@ARGV) > 0) ? @ARGV : keys(%filename);
+my @charsets = (scalar(@ARGV) > 0) ? @ARGV : sort keys(%filename);
 
 foreach my $charset (@charsets)
 {