lib/PublicInbox/SharedKV.pm | 8 +++-----
 t/shared_kv.t               | 2 +-

diff --git a/lib/PublicInbox/SharedKV.pm b/lib/PublicInbox/SharedKV.pm
index 072c94ca553827371a4740420d8c6da32c7d1b5c..94f2429fdda2eaf51b3c378b5bd4c383bec43b8b 100644
--- a/lib/PublicInbox/SharedKV.pm
+++ b/lib/PublicInbox/SharedKV.pm
@@ -44,10 +44,7 @@
 sub new {
 	my ($cls, $dir, $base, $opt) = @_;
 	my $self = bless { opt => $opt }, $cls;
-	unless (defined $dir) {
-		$self->{tmpdir} = $dir = tempdir('skv-XXXXXX', TMPDIR => 1);
-		$self->{tmpid} = "$$.$self";
-	}
+	$dir //= $self->{"tmp$$.$self"} = tempdir("skv.$$-XXXX", TMPDIR => 1);
 	-d $dir or mkdir($dir) or die "mkdir($dir): $!";
 	$base //= '';
 	my $f = $self->{filename} = "$dir/$base.sqlite3";
@@ -148,7 +145,8 @@ }
 
 sub DESTROY {
 	my ($self) = @_;
-	rmtree($self->{tmpdir}) if ($self->{tmpid} // '') eq "$$.$self";
+	my $dir = delete $self->{"tmp$$.$self"} or return;
+	rmtree($dir);
 }
 
 1;
diff --git a/t/shared_kv.t b/t/shared_kv.t
index 6f6374f28f351ccf76b7451f0d1ee280b2212052..fcae688a31dd403b2b87b9e7f03fcd7d571c2720 100644
--- a/t/shared_kv.t
+++ b/t/shared_kv.t
@@ -9,7 +9,7 @@ use_ok 'PublicInbox::SharedKV';
 my ($tmpdir, $for_destroy) = tmpdir();
 local $ENV{TMPDIR} = $tmpdir;
 my $skv = PublicInbox::SharedKV->new;
-my $skv_tmpdir = $skv->{tmpdir};
+my $skv_tmpdir = $skv->{"tmp$$.$skv"};
 ok(-d $skv_tmpdir, 'created a temporary dir');
 $skv->dbh;
 my $dead = "\xde\xad";