Hello

Another error I noticed on the same day that this issue occured smtp sending issue was this:
DB Error #1205
[UPDATE ost_session SET session_expire = (NOW() + INTERVAL 21600 SECOND), user_id = 52, session_updated = NOW() WHERE ost_session.session_id = 'cvbf5t8hkvl84pqctkji2f94ae' LIMIT 1] Lock wait timeout exceeded; try restarting transaction

---- Backtrace ----
#0 (root)/include/mysqli.php(207): osTicket->logDBError()
#1 (root)/include/class.orm.php(3482): db_query()
#2 (root)/include/class.orm.php(658): MySqlExecutor->execute()
#3 (root)/include/class.ostsession.php(374): VerySimpleModel->save()
#4 (root)/include/class.ostsession.php(364): DatabaseSessionRecord->save()
#5 (root)/include/class.ostsession.php(356): DatabaseSessionRecord->commit()
#6 (root)/include/class.ostsession.php(536): DatabaseSessionRecord->expire()
#7 (root)/include/class.session.php(369): DatabaseSessionStorageBackend->expireRecord()
#8 (root)/include/class.ostsession.php(234): osTicket\Session\AbstractSessionStorageBackend->expire()
#9 (root)/include/class.ostsession.php(262): osTicketSession::expire()
#10 (root)/include/class.usersession.php(163): osTicketSession::renewCookie()
#11 (root)/scp/staff.inc.php(104): StaffSession->refreshSession()
#12 (root)/scp/tickets.php(17): require('...')
#13 {main}

This error occured in total 102 times in span of 45min (until I restarted mysql). I noticed different user id's involved which makes sense when table was locked. Sadly I didn't check which query was holding the lock on the table..
No errors in php, mysql or apache logs during that time. After that incident I added query + slow_query log to mysql.

I noticed that ost_session inserts/updates are mentioned there but maximum time was 6s, which is slow of course but nothing near the mysql timeout.

    erikpahlberg

    MySQL times out. Probably waiting on a long running query. You can enable MySQL slow query logs and track slow queries and see what’s going on.

    Cheers.

      Yes, that's what I did, and in this log I see that inserting/updating ost_session table takes up to 6 seconds to complete. Timeout is 50 sec so I'll probably have to wait until it happens again to debug this issue.

      how many entries do you have in the session table?
      (out of curiosity how big is your database?)
      What's your server hardware for the site?
      Are all of your database tables using the InnoDB engine?

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