We recently made the jump to MySQL 4.1 at SitePoint and it’s mostly been smooth sailing. Though I have to admit that it hasn’t offered any of the performance increases that I had hoped for.
Just a heads up – as I’ve not seen this covered anywhere yet – that the default filenames created by the binary logger have changed.
In all prior versions, they were of this format:
Where xxx increments by 1 every time the logs are rotated. 001, 002, 003, etc.
(Note that the “mysql_update_log” prefix is configurable)
In MySQL 4.1, however, they are of this format:
The point obviously being to cater for installations that reset the counter a lot less frequently than we do. We never get beyond 30 before a complete snapshot and a restart of update logging.
This of course broke our script that compresses these (enormous) logfiles for backup purposes and required a little Friday hack to get back on track.
No mention of this behavioural change in the 4.0 -> 4.1 upgrade FAQ.