Interesting Things Today
Message "undefined method 'join'" on gem installation during deployment to Engine Yard turned out to be the result of an upgrade of RubyGems from 1.3.5 to 1.3.6. The new version no longer requires stringio which broke bundler 0.8.1. The solution was to install the gem bundler08 -v0.8.4 on the server and then rerun 'gem bundle.'
A mysql 'Error 139' was traced to a mysql 5.0 innodb table that had enough varchar(255) and text columns such that the total bytes in the row exceeded 8k bytes. This is allegedly fixed in 6.0 (maybe 5.1).
Finally a team noticed the new 'touch' option in rails 2.3.4 on has_many and belongs_to attribute that allows you to update the updated_at attribute of child and parent objects. They'd implemented their own observer pattern to do the same thing but this was much easier.