Zmmsgtrace very slow

[Cesco]

Hi, recently I had a problem at work with a user sending the same mail to every other account (more than 3000) by mistake and some other answering back to the whole list :-(

After that I noticed that the zmmsgtrace command has become very slow, especially with the -r option. Monitoring the server with the top command, I can see the mysqld service pushing the CPU to 100% while the zmmsgtrace does its job, but this lasts for almost 3 minutes, whereas before it took from 5 to 10 seconds.

I'm sure that something got screwed after that episode. Any suggestion for a possible solution? Thanks!