Just found a very nice article, “Tips for Optimizing Rails on Oracle”:http://www.oracle.com/technology/pub/articles/mearelli-optimizing-oracle-rails.html?msgid=5676684, on OTN (Oracle Technology Network). Definitely worth reading if you are working with Rails and Oracle:
bq. In this article you dug a bit into how connections to an Oracle database are configured in a Rails application, and you have seen how the framework has been updated in the 1.2 release to have better performances thorough the use of the cursor_sharing and prefetch_rows parameters (while waiting for a real bind variable implementation).
You have also examined the Rails migration commands that are relevant to tuning the database (specially creating/removing indexes).
Finally, as you’ve learned, a good understanding of both how Rails builds the SQL from the code and how the database executes them is needed to get the best performance. The provided plugins should help here.