The last few months, I’ve had the pleasure of using utPLSQL v3, a unit testing framework for PL/SQL, on a new project that I’m working on. Sure – writing tests takes a bit extra time, but it’s such a huge help when you’re constantly refactoring a system that grows from zero.
We found a bug in some old code. And we fixed it. Then other stuff started failing. It turned out that there were some other code, using the same function, that worked because of the bug. That forced us to roll back the fix and thereby re-introduce the initial bug that weren’t as critical.
So – we had to find a way to find out which code-paths were working because of the bug so we could fix those.
In my previous post, I showed how you can add a fake hint to tag the origin of a duplicated statement and as a side-effect make it unique. What if you regret and can’t remember where it was. Or you want to review old hinted statements after an upgrade to a newer version of the database/optimizer.
Finding duplicate SQL statements using PL/Scope is easy. If you cannot merge them, how can you differentiate between which source is being run?
On our production system we’ve enabled the collection of PL/Scope metadata. Since this is a SmartDB/PinkDB-application (business logic and queries in the database), this makes it really easy to find, inspect and modify the source code of queries that doesn’t run efficiently. Now it’s even easier using reports in Oracle SQL Developer.
Oracles function result cache (FRC) can in certain cases give a considerable performance boost. Application context is another useful feature. How does FRC work when the function result relies on context-settings? And how can we make them play well together?
Can we use PL/Scope to find dead and potentially dead PL/SQL code? Yes! And it takes less than a second!
PL/Scope records declarations and usages of procedures and functions, so it should be easy to do a quick comparison of what’s declared and what’s actually used.