We have a lot of data -- apparently about 9,000 tables in an RDBMS.  It's 
in Oracle now.  As a fan of open source solutions, I would prefer to use 
MySQL or other open source RDBMS, but at what cost?  Before I even 
consider moving data to MySQL from Oracle, I want to know what Oracle can 
do that MySQL (or other FOSS product) cannot do.  Have any of you studied 
this or do you know of any reasonably serious comparative research or 
reviews?  Thanks.

Mike