Bug: The single-table inheritance mechanism failed to locate the subclass: 'MiqEmsRefreshCoreWorker'.

[jrafanie]

We found there was a missing worker class that was persisted in the miq_workers table but was subsequently removed in newer versions:

gems/activerecord-6.0.4.6/lib/active_record/inheritance.rb:234:in `rescue in find_sti_class': The single-table inheritance mechanism failed to locate the subclass: 'MiqEmsRefreshCoreWorker'. 

https://github.com/ManageIQ/manageiq/pull/17196 removed this worker and the PRs: https://github.com/ManageIQ/manageiq-providers-vmware/pull/216 added MiqEmsRefreshCoreWorker and MiqVimBrokerWorker to the provider https://github.com/ManageIQ/manageiq-providers-vmware/pull/488 removed MiqEmsRefreshCoreWorker from the provider https://github.com/ManageIQ/manageiq-providers-vmware/pull/506 removed MiqVimBrokerWorker from the provider

We didn't write a migration to remove these rows from miq_workers leading to the reported issue.

Note, this code in the server is there to remove these unknown worker class rows at startup but because it's mixing "process killing" and "miq_workers row removal", it's only removing these unknown rows for the current/local server. Additionally, it seems problematic to kill valid worker rows for another server, especially if it's active. If you upgrade from one old version to another and old servers are not started on the new code, it will never clean them up.

TODO:

• [ ] Write a data migration to remove the removed classes from miq_workers like we've done with prior worker class removals
• [ ] Split the process killing from row removal. ref
• [ ] Consider making a public method and perhaps we can add it to MiqServer.seed or in the tools directory and would do something like this: MiqServer.all.each {|s| s.worker_manager.send(:kill_unknown_worker_processes)} (but without trying to kill the actual Process) ref

[miq-bot]

This issue has been automatically marked as stale because it has not been updated for at least 3 months.

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