tool_excimer in a production environment causes dmlwriteexceptions in the automated backup process

[asmraap]

Our automated backup process that runs every night had a lot of backups (10%) that ended with status 800 and a dmlwwriteexception in the backup logs. Because this happened in our production environment I wasn't able to debug the problems here. I changed the innodb buffer size, as this had become too small for our database, but after this change the errors still continued in our backup.
I decided to uninstall the tool_excimer plugin and the next day all the backups were finished good again without the errors with the dmlwriteexceptions. The plugin settings were the default settings as they were after installation.

[brendanheywood]

Thanks, can you shed any light on the 800? That is a non standard http code. If you are able to get this failing on a staging server and provide a stack trace that would be great

[asmraap]

Hi Brendan, it's the status of the backup process, which should end with 1000
Unfortunately I can't debug this in production, and in our other environments I can't reproduce this problem

[asmraap]

In the task logging I see also less failures last week since I uninstalled the tool_excimer plugin, it seems that running tasks in Moodle cron together with the plugin causes database (locking?) problems.