Recently we migrated 18 MySQL MyISAM tables to InnoDB. (We would have changed another 20 smaller ones if we weren’t hamstrung by a OS issue we’ll be resolving soon.)

The change has significantly reduced the overall load as well as short-term spikes on our master database. Below you see a chart of our primary master’s 15, 5 and 1 minute average loads over the last 3 weeks. As you can see this critical machine is now much calmer and ready to handle significantly more capacity.

Recent Load on our MySQL Master Server

It turns out that the benefits of row-level locking, in many cases, is not just for high volume UPDATE tables anymore and the reads off the slaves are no slower than MyISAM. This, apparently, was consistently agreed to at this year MySQL Conference in April. Big props to Greg and Laine for realizing this and making it happen.