From d4362262028b6efadcfa468ae1e81dcf9bd006a8 Mon Sep 17 00:00:00 2001 From: Jonathan Druart Date: Thu, 9 Feb 2017 12:44:38 +0100 Subject: [PATCH] Bug 15854: Use a READ and WRITE LOCK on message_queue MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To make sure we will not never get a race conditions for these kinds of notices, we need to add a LOCK on the message_queue table. This does not smell the best way to do that, but I faced deadlock issues when I tried to use "UPDATE FOR" https://dev.mysql.com/doc/refman/5.7/en/innodb-locking-reads.html https://dev.mysql.com/doc/refman/5.7/en/lock-tables.html https://dev.mysql.com/doc/refman/5.7/en/commit.html To test this patch, or another solution, you need to apply manually this change: my $message = C4::Message->find_last_message($borrower, $type, $mtt); unless ( $message ) { + sleep(1); C4::Message->enqueue($letter, $borrower, $mtt); } else { And repeat the test plan from first patch. Do not forget to truncate the message_queue table. Followed test plans, works as expected. Signed-off-by: Marc VĂ©ron --- C4/Circulation.pm | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/C4/Circulation.pm b/C4/Circulation.pm index 4b32008..b10a6c2 100644 --- a/C4/Circulation.pm +++ b/C4/Circulation.pm @@ -3366,6 +3366,7 @@ sub SendCirculationAlert { }); my $issues_table = ( $type eq 'CHECKOUT' || $type eq 'RENEWAL' ) ? 'issues' : 'old_issues'; + my $schema = Koha::Database->new->schema; my @transports = keys %{ $borrower_preferences->{transports} }; for my $mtt (@transports) { my $letter = C4::Letters::GetPreparedLetter ( @@ -3383,13 +3384,19 @@ sub SendCirculationAlert { } ) or next; + $schema->storage->txn_begin; + C4::Context->dbh->do(q|LOCK TABLE message_queue READ|); + C4::Context->dbh->do(q|LOCK TABLE message_queue WRITE|); my $message = C4::Message->find_last_message($borrower, $type, $mtt); unless ( $message ) { + C4::Context->dbh->do(q|UNLOCK TABLES|); C4::Message->enqueue($letter, $borrower, $mtt); } else { $message->append($letter); $message->update; } + C4::Context->dbh->do(q|UNLOCK TABLES|); + $schema->storage->txn_commit; } return; -- 2.1.4