It is possible to create a transparent database to another production database server? I mean, testing new functions in a production database is too dangerous. What if we create a database which based on Copy On Write mechanism (because don't want to copy a big amount of data every time), and make some modification on that? The original production database will not modified, only the COW database. After the test, the COW database can be dropped or saved, etc., but the original can operate without any kind of danger.
Doe this solution exist? Has anyone implemented it?