I like to define a five-point touch system for my database upgrades. If the new version doesn't change my life in five ways, then it's not a significant upgrade. I'll typically quantify my need by approximating how many hours I spend each week performing certain tasks, and then estimate how much time the upgrade will save me. If I spend five hours every week dealing with resource usage and the new release will do it automatically, then I figure the upgrade will save me five hours a week. Now all I have to do is quantify four other features the same way, and I can sell it to management.
I expect most Oracle Database shops will find at least five of these life changers in Oracle Database 11g. But there's one feature, Real Application Testing, that's so compelling, it's almost enough reason to upgrade on its own. There's not a shop out there that doesn't make code changes, and they all need a solid way of reproducing production workloads to certify those changes without affecting the production environment. Real Application Testing does the trick.
Combining Database Replay and SQL Performance Analyzer, Real Application Testing allows you to capture a workload and its performance stats and replay it, either on the same box or on another box, and compare the performance results. This level of insight into comparative workloads is something that most database vendors are still struggling with.
Other big new features in Oracle Database 11g are Snapshot Standby, Active Data Guard, Advanced Compression, resource management improvements, SQL tuning, and health checks.
Active Data Guard is a bit hampered by difficult installation and poor documentation, at least on Windows, but it's a must-have for any DBA wanting to put idle standby databases to good use. Similarly, Data Guard's new Snapshot Standby feature will help DBAs get a grip on change control or application testing.
I would be cautious in implementing Advanced Compression, though. I don't think it's implemented as well as it could be, and it's expensive enough that the cost benefits won't be realized by the largest portion of customers. However, handled correctly, Advanced Compression can help a DBA achieve a high level of data de-duplication.
Result Cache is another new feature that will give you exactly what you ask for, so it should be used with caution. But the tests I ran showed that beautiful results are possible if you understand the technology, clearly define your goals, and work within the bounds of your system.
Automatic health monitoring and data corruption checks also highlight this release. Oracle Database 11g is both proactive and decisive when the possibility for corruption arises.
Overall, this is a very strong release. It has a couple of bumps, but nothing that should hold anyone back from an upgrade. And there are so many new features, there's bound to be something for everyone -- large and small shops alike.