Some bugs can have a high impact if it causes data corruption, security issues or simply causes MySQL to crash. But what about small bugs and small usability issues? This entry from the MySQL 5.6.8 release notes is an interesting one: InnoDB: On startup, MySQL would not start if there was a mismatch between the value of the innodb_log_file_size configuration option and the actual size of the ib_logfile* files that make up the redo log . This behavior required manually removing the redo log files after changing the value of innodb_log_file_size . The fix causes MySQL to write all dirty pages to disk and re-create the redo log files during startup if it detects a size mismatch. (Bug #14596550) So previously you had to shutdown MySQL without fast shutdown enabled, then move the ib_logfile's away and start MySQL again. This is not too hard or complicated. But I have seen some seriou...

I've reviewed the Instant InnoDB book. It's a good starting point if you're learning about InnoDB, which is used for most MySQL installations. As a consultant I've seen many situations where some basic InnoDB setting (buffer pool size, log file size, file per table) can have a huge effect on the performance of the database and make it easier to manage. The website of the book can be found here .