By easier I mean that patches for recent versions of MySQL 5.0 have been published. And if you don't want to go through the trouble of applying the patch, I imagine that Bluehost.com has it running on their hosted servers.
The MySQL Performance blog post describes using the microslow patch in combination with SHOW USER_STATISTICS output to debug workload problems. I hope they describe the process in greater detail in another blog post. I use user and table accounting as the first step in debugging workload problems. With that data I determine which users and tables create the majority of the load and then I use SQL statement logging or sampling from SHOW PROCESSLIST to determine the statements that might be the problem.
The external development community is growing, if slowly, and I am happy to see this. We have had some nice patches and major features and I look forward to more. I am sure I have left others off of this list -- let me know.
- SHOW PROFILES from Proven Scaling
- Reduced memory usage for the HEAP engine from eBay and Igor
- Microslow logging from Percona
- InnoDB performance improvements from Yasufumi Kinoshita at NTT (here and here)
- The Google patch
- PBXT storage engine and blob streaming engine courtesy of Primebase
- InnoDB (it is GPL after all)
- Dormando's proxy
- Support for memcached