script/public-inbox-extindex | 4 +++-

diff --git a/script/public-inbox-extindex b/script/public-inbox-extindex
index 607baa3e0ef785b3e8cd31d06f5449a55bc07352..17986f606e93f16872aa7e4df2d0ad72cad4fe59 100644
--- a/script/public-inbox-extindex
+++ b/script/public-inbox-extindex
@@ -33,7 +33,9 @@ 		all help|h))
 	or die $help;
 if ($opt->{help}) { print $help; exit 0 };
 die "--jobs must be >= 0\n" if defined $opt->{jobs} && $opt->{jobs} < 0;
-
+require IO::Handle;
+STDOUT->autoflush(1);
+STDERR->autoflush(1);
 # require lazily to speed up --help
 my $eidx_dir = shift(@ARGV) // die "E: $help";
 local $SIG{USR1} = 'IGNORE'; # to be overridden in eidx_sync