How You Perform the Upgrade
Note: Back up all data before starting.
The overall strategy for upgrading is as follows:
1. Copy databases and applications.
Copy the databases to be upgraded into the new version development installation, and make a copy of all associated applications.
It is important that your original version development installation remain; if the upgrade is unpredictably delayed, you will still have your original environment in which to fix mission-critical applications, if necessary.
2. Change databases and applications.
Make any changes needed to the database definition or the application source code so that they function with the new version.
If you are upgrading from a recent version (for example, from Ingres II 2.0 to Ingres 2.6), few or no changes are necessary. If you are upgrading from Ingres 6.4, this step can be lengthy.
All compatibility changes will be reflected back into the original version development installation. Thus, if the upgrade is delayed for some reason, no work will be lost.
3. Test applications.
Test your critical applications in the new-version development environment.
Fix any problems or performance issues before your production upgrade. The fix will nearly always be compatible with your original version as well, and therefore can be reflected back into your standard development environment.
4. Practice the upgrade.
Practice the upgrade using the test installation. Ideally, the test installation should be a duplicate of production. Repeat the trial upgrade as often as necessary to achieve a trouble-free upgrade.
Note: While practicing the upgrade, stop application development. You want the live upgrade to run exactly like the practice one, without involving new and untested factors.
5. Upgrade to the production system.