Debugging mysql stored procedures

The other day I needed to figure out why the heck my mysql stored procedure wasn't working. I poked around for a way to do the most fundamental debugging possible: print out a log message.

Postgres accomplishes this by using the RAISE keyword, but mysql didn't seem to have a comparable function.

After a bit of Googling around I came across this article where the author recommends a technique for doing just this kind of debugging.

The technique is embarrassingly simple, and I wish I had thought of it: simply create a debug_log table that contains a text field in it. Then write a debug function that inserts into that table.

Duh. Now, why didn't I think of that?

It's a simple and brilliant way to get around the fact that mysql doesn't seem to provide any other debugging facilities.

Get all the details here.