Hi Chris I don't know whether this will help (the details don't exactly match) but there was a bug posted last year (https://www.mail-archive.com/search?l=koha-bugs@lists.koha-community.org&q=subject:%22%5C%5BKoha%5C-bugs%5C%5D+%5C%5BBug+23690%5C%5D+During+checkout%2C+window+hangs+with+a+pop+up+%5C%22Loading...you+may+continue+scanning.%5C%22%22&o=newest&f=1) that made the checkout window hang with a pop up window "Loading ... you may continue scanning" - does this sound like your problem? With kind regards from the Dalton McCaughey Library Team Carlos Lopez Dalton McCaughey Library | 29 College Crescent, Parkville, VICTORIA 3052 Ph: 03 9340 8888 ext.1 | library@dml.vic.edu.au | library.dmlibrary.org.au -----Original Message----- From: Koha <koha-bounces@lists.katipo.co.nz> On Behalf Of Chris Brown Sent: Monday, 21 June 2021 4:42 PM To: koha <koha@lists.katipo.co.nz> Subject: [Koha] Need help with Koha instance that refuses to do checkouts Dear Koha Community Following up my post on 12 June I am repeating my call for help as Koha is effectively unusable right now at one of our libraries. We are running Koha 19.11 on Debian 9.11 (stretch). This supports 5 Koha instances for some of the volunteer-run libraries in Sheffield. It has been stable and working fine for many months. Currently we have a serious problem with one of these instances. Any attempt to check out a book hangs (never completes) and we see /usr/share/koha/intranet/cgi-bin/circ/circulation.pl consuming most of the CPU cycles (stuck in a loop perhaps?). On one occasion I noticed it was renew.pl consuming all the CPU. I have tried disabling plack for this instance, and have rebuilt the zebra index, but the problem persists. There is nothing obvious reported in the log files, though I may not be looking in the right places. I cannot see any obvious problems with the configuration, though again I might be looking at the wrong things. The other 4 instances are working OK. *Any advice on how to debug or fix this would be greatly appreciated.* Does anyone know how to turn on tracing of MySQL transactions? I was wondering if looking at the activity at the database end might help. Thanks and Best Regards, Chris Brown (Voluntary Libraries in Sheffield) _______________________________________________ Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha