How to manage a growing MySQL slow_log table? I see MySQL supports storing slow_log as a table (internally using mysql/slow_log.CSV file), and this appears convenient, but is it a feature I should use in production? I found online articles on the importance of temporarily disabling slow query logging while rotating the file log, but what's the best practice for managing slow_log.CSV? eg. copy and truncate table or rotate the slow_log.CSV just like db-slow.log?
First of all, I discourage you from using the slow log with TABLE output, in production. The reason is that writes are locking, which limits the concurrency of your workload.

Moreover, CSV stored engine does not support indexes. Any non-trivial query will be very slow, so I don't see any advantages in doing this. Of course you could use MyISAM and add indexes, but then writes will become more expensive.

That said, the correct way to "rotate" the table is copying it and than truncate it. You will probably lose some queries every time: the ones ran after the copy but before the TRUNCATE TABLE statement.