script/public-inbox-index | 6 +++---

diff --git a/script/public-inbox-index b/script/public-inbox-index
index 73f88ac6bee72fd0eabc3497881cf42e3392cc97..db7ebbab6421ec2cc1b849e4259b2ac82d6d745b 100755
--- a/script/public-inbox-index
+++ b/script/public-inbox-index
@@ -31,7 +31,7 @@ 	'--jobs|j=i' => \$jobs,
 	'--prune' => \$prune,
 );
 GetOptions(%opts) or die "bad command-line args\n$usage";
-die "--jobs must be positive\n" if defined $jobs && $jobs <= 0;
+die "--jobs must be positive\n" if defined $jobs && $jobs < 0;
 
 my @dirs;
 
@@ -101,11 +101,11 @@ 	if (ref($repo) && ($repo->{version} || 1) == 2) {
 		eval { require PublicInbox::V2Writable };
 		die "v2 requirements not met: $@\n" if $@;
 		my $v2w = eval {
-			local $ENV{NPROC} = $jobs;
+			local $ENV{NPROC} = $jobs if $jobs;
 			PublicInbox::V2Writable->new($repo);
 		};
 		if (defined $jobs) {
-			if ($jobs == 1) {
+			if ($jobs == 0) {
 				$v2w->{parallel} = 0;
 			} else {
 				my $n = $v2w->{partitions};