Mysterious message in Rails output at launch

For the last couple of days, the following message has started showing up on stdout (*not* in the .log file) at startup when I run script/ console, or start mongrel in my development environment, or run a Rails unit test: -- tables()    -> 0.0210s

Apparently this is telling my about execution time for a method call somewhere. But I never asked for it.

Where is this message coming from? I don't recall turning on any logging, or installing any plugins or new gems. I've grepped through all the code I can find. It's very mysterious.

Any suggestions on where to look next are greatly appreciated.

Thanks, -Jason