lib/PublicInbox/SearchIdx.pm | 2 +-

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index 0ee077910c8b0d6f0ff7837d69250daf18e86037..fa5057fd6851b5f668ead4b84b5b0ff46f8c0325 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -394,7 +394,7 @@ 	$self->{term_generator} = $tg;
 }
 
 # increments last_thread_id counter
-# returns a 64-bit integer represented as a hex string
+# returns a 64-bit integer represented as a decimal string
 sub next_thread_id {
 	my ($self) = @_;
 	my $db = $self->{xdb};