Why is maintenance logging a 'Maintenance tasks not run: could not acquire lock' message?

Maintenance locks tables to prevent multiple maintenance procedures from running at the same time.
The 'Maintenance tasks not run: could not acquire lock' message means that a table is locked and maintenance will not run.

It could be that maintenance really is running and a 2nd maintenance procedure was ordered which did not run because the tables were locked. In this case you should let maintenance complete and wait before calling for a further maintenance procedure to run.

Two instances being called could mean that you have both auto-maintenance and a cron job for maintenance enabled. Only one will run per Operation Interval (default of 1 hour).

There is high probability that you might be getting this message if you are using Auto-maintenance and it gets called many times within an Operation Interval.

If you keep an eye on the openx/var/maintenance.log and never see any messages except for this locked warning, then it could be that maintenance is never able to run because the tables are not unlocking.

In this case, try:

1. Restart MySQL, which should release the locks
2. Execute repair commands on the 'log_maintenance_%' tables.