Bradley C. Kuszmaul's blog

Thanks, I appreciate the effort you are taking to find the truth. -Bradley

I didn’t mean to be flaming, I’m sorry if it seemed that way. And I apologize for not noticing that the response to my comment wasn’t from the original author.

You are correct that indexes cost something in InnoDB. However, if you measure InnoDB you will likely find it is much faster than MyISAM for insertions when maintaining an index on a large table. My measurements (and others, such as Mark Callaghan at Facebook) say that InnoDB is faster (maybe 4x) for this kind of load.

Using MyISAM is just asking for poor performance. Try using a storage engine that is actually good at indexing.