Oracle 12c upgrade – backwards compatible with 11g

There is no in-place upgrade possible but the existing exp utility is still supported for importing dmp files.

Some of the issues you need to research are:

• I have taken an export from an 8i database and imported it into an 11g with no issues. Importing into 12 should not be a problem but planning is everything!
• will you use the same character set? Often organizations start with western only and need to use UTF16 for more compatibility with other languages.
• do yourself a favour and do an install on a new machine with new hardware. 12 requires more of everything, memory, hard drive.
• many 8i parameters are not supported so you need to establish if there are any custom settings that you need equivalents for

Of course this would need to be tested.

There are multiple solutions to this problem but the driving issues are cost, allowable downtime and complexity.

• Golden Gate could be purchased with a one year license and will do a zero downtime upgrade from Oracle 8i to 12. You still have to upgrade from 8.05 to 8i.
• Your life could be simplified by using VmWare P2V to convert the machine to a virtual machine without any downtime. This method allows you to:
  • get your production database on better hardware which should improve the speed of most operations
  • allows you to make a copy of the machine, put it on a different subnet and start testing various strategies
• I have imported schemas from our Oracle 8i database directly into Oracle 11.2 without issues. Your mileage may vary depending on character sets, licensed features and any unorthodox strategies your programmers have in the PL/SQL code.

One method that could be easily tested:

• buy a new server with some serious hardware like 32GB RAM, install VMWare Esxi
• convert your old machine to a virtual
• create a development copy of the Oracle 8.05
• install another virtual machine with Oracle 12
• install another virtual machine with Oracle 10XE or 11XE
• take snapshots of all the machines with no changes
• take an export of the 8.05 development, import into Oracle 10XE or 11XE, test and verify
• data pump to the 12 database
• verify the data on 12 and offline the 8.05 and oracle 10XE or 11XE

This method needs downtime. A weekend should be more than adequate and only costs you a new server, Oracle 12 licence and some VMWare software licenses. Keep in mind that testing and verification can take more time than importing the data.