Forum OpenACS Q&A: Trezzo's recompile_all_objects for Oracle
If you're lucky, you will never notice, because Oracle will attempt to recompile the invalidated objects in place the next time they are used. But if, say, you changed the interface to the function you just replaced, anything calling it will now break, and if replacing the function is all you do, you will probably not find out things are broken until runtime!
The solution to this (for Oracle) is Trezzo's super-useful
PL/SQL procedure. After you make you changes, just do "
recompile_all_objects" in sqlplus.