Things I’ve learned about perltidy.
When returning a hashref from a subroutine, make sure to explicitly give the ‘return’ command, or else perltidy will get confused, think it’s a bare block, and format it strangely.
Similarly, if the last statement of a script is complex, with nested subrefs etc, adding the trailing semicolon can change how perltidy [...]

V. Satheesh Babu has an interesting article on using Oracle Stored Procedures to add an extra layer of security to web applications.