https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=27707 --- Comment #1 from Jonathan Druart <jonathan.druart@bugs.koha-community.org> --- I did some testing and I confirm that the txn is not needed here. use Koha::Database; my $schema = Koha::Database->new->schema; $schema->txn_do(sub { $schema->txn_do( sub { my $dbh = $schema->storage->dbh; say "getting locks"; $dbh->do(q|LOCK TABLE message_queue READ|); $dbh->do(q|LOCK TABLE message_queue WRITE|); say "locked!"; sleep 10; say "unlocking"; $dbh->do(q|UNLOCK TABLES|); say "unlocked!"; }); }); Start several parallel processes. Remove the nested txn_do, try again. -- You are receiving this mail because: You are watching all bug changes. You are the assignee for the bug.