lib/PublicInbox/SharedKV.pm | 30 +++++++++++++++++++++++-------
 t/shared_kv.t               |  3 +++

diff --git a/lib/PublicInbox/SharedKV.pm b/lib/PublicInbox/SharedKV.pm
index d49a39c1b28ce38d95cb76229a91c1633563c08e..90ccf2b4388c34dc48b21ad647c60b47b1ab98c0 100644
--- a/lib/PublicInbox/SharedKV.pm
+++ b/lib/PublicInbox/SharedKV.pm
@@ -9,7 +9,7 @@ use strict;
 use v5.10.1;
 use parent qw(PublicInbox::Lock);
 use File::Temp qw(tempdir);
-use DBI ();
+use DBI qw(:sql_types); # SQL_BLOB
 use PublicInbox::Spawn;
 use File::Path qw(rmtree make_path);
 
@@ -59,9 +59,12 @@
 sub set_maybe {
 	my ($self, $key, $val, $lock) = @_;
 	$lock //= $self->lock_for_scope_fast;
-	my $e = $self->{dbh}->prepare_cached(<<'')->execute($key, $val);
+	my $sth = $self->{dbh}->prepare_cached(<<'');
 INSERT OR IGNORE INTO kv (k,v) VALUES (?, ?)
 
+	$sth->bind_param(1, $key, SQL_BLOB);
+	$sth->bind_param(2, $val, SQL_BLOB);
+	my $e = $sth->execute;
 	$e == 0 ? undef : $e;
 }
 
@@ -88,20 +91,30 @@ 		substr($pfx[0], 0, 0, '%') if $anywhere;
 	} else {
 		@pfx = (); # [0] may've been undef
 	}
-	map { $_->[0] } @{$self->dbh->selectall_arrayref($sql, undef, @pfx)};
+	my $sth = $self->dbh->prepare($sql);
+	if (@pfx) {
+		$sth->bind_param(1, $pfx[0], SQL_BLOB);
+		$sth->bind_param(2, $pfx[1]);
+	}
+	$sth->execute;
+	map { $_->[0] } @{$sth->fetchall_arrayref};
 }
 
 sub set {
 	my ($self, $key, $val) = @_;
 	if (defined $val) {
-		my $e = $self->{dbh}->prepare_cached(<<'')->execute($key, $val);
+		my $sth = $self->{dbh}->prepare_cached(<<'');
 INSERT OR REPLACE INTO kv (k,v) VALUES (?,?)
 
+		$sth->bind_param(1, $key, SQL_BLOB);
+		$sth->bind_param(2, $val, SQL_BLOB);
+		my $e = $sth->execute;
 		$e == 0 ? undef : $e;
 	} else {
-		$self->{dbh}->prepare_cached(<<'')->execute($key);
+		my $sth = $self->{dbh}->prepare_cached(<<'');
 DELETE FROM kv WHERE k = ?
 
+		$sth->bind_param(1, $key, SQL_BLOB);
 	}
 }
 
@@ -110,7 +123,8 @@ 	my ($self, $key) = @_;
 	my $sth = $self->{dbh}->prepare_cached(<<'', undef, 1);
 SELECT v FROM kv WHERE k = ?
 
-	$sth->execute($key);
+	$sth->bind_param(1, $key, SQL_BLOB);
+	$sth->execute;
 	$sth->fetchrow_array;
 }
 
@@ -121,9 +135,11 @@ 	my $oldval = get($self, $key);
 	if (defined $newval) {
 		set($self, $key, $newval);
 	} else {
-		$self->{dbh}->prepare_cached(<<'')->execute($key);
+		my $sth = $self->{dbh}->prepare_cached(<<'');
 DELETE FROM kv WHERE k = ?
 
+		$sth->bind_param(1, $key, SQL_BLOB);
+		$sth->execute;
 	}
 	$oldval;
 }
diff --git a/t/shared_kv.t b/t/shared_kv.t
index 8b4f9c29ea9553971208a52ccf67b27a8e931b8d..8dfd3b2585780299a0ad15d3a854ac3995de9005 100644
--- a/t/shared_kv.t
+++ b/t/shared_kv.t
@@ -42,5 +42,8 @@ undef $skv;
 ok(!-d $skv_tmpdir, 'temporary dir gone');
 $skv = PublicInbox::SharedKV->new("$tmpdir/dir", 'base');
 ok(-e "$tmpdir/dir/base.sqlite3", 'file created');
+$skv->dbh;
+ok($skv->set_maybe('02', '2'), "`02' set");
+ok($skv->set_maybe('2', '2'), "`2' set (no match on `02')");
 
 done_testing;