This is a great example of the complexity tradeoff when you choose performance over atomicity. Delayed::Job has lost favor lately, but the semantics of the job becoming visible to the queue runner atomically with the related new record are hard to beat.
Note that even in the proposed solution, after_commit hooks offer no guarantee that the job will ever be enqueued, if for example redis is unavailable, or your process gets reaped between when the database commit and when the after_commit hook gets fired -- the commit has already happened. So if it's really important that your asynchronous task be queued, keeping the queue in your DB has some advantages.
Note that even in the proposed solution, after_commit hooks offer no guarantee that the job will ever be enqueued, if for example redis is unavailable, or your process gets reaped between when the database commit and when the after_commit hook gets fired -- the commit has already happened. So if it's really important that your asynchronous task be queued, keeping the queue in your DB has some advantages.