Optimizing select projectionsInterlude, refactoring
time to read 2 min | 256 words

So we got an order of magnitude performance boost, without really doing much, to be honest. But the code is starting to look really ugly, and future optimizations are out until we fix it.

Since we don’t really care about the internal details, we can do two things in one move. First, we’ll cleanup the code by introducing a delegate that will abstract the handling and the second is that this delegate will also allow us to handle caching of additional values simple by way of capturing the delegate state.

Here is what the code looks like:

Note that we have it broken apart into distinct steps, and the ProjectViaJint method is self contained and any caching it needs is done internally. This is much needed refactoring if we want to be able to continue to optimize this code, and it runs in about the same speed as the previous version, so we didn’t hurt anything there.

With this in place, we can see how much better we can make things.

Before we go on, I want to emphasis that this code is actually making a lot of assumptions. The passed dictionary must always have the same set of fields, for example, otherwise we may see a value from a previous iteration. No null handling or error handling is in place, we aren’t showing the unpacking of the values from the JS env to our code, and plenty of other stuff. That isn’t that important at this point, because I’m showing the progression of optimizations, rather then production code.

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More posts in "Optimizing select projections" series:

  1. (01 Sep 2017) Part IV–Understand, don’t do
  2. (31 Aug 2017) Interlude, refactoring
  3. (30 Aug 2017) Part III
  4. (29 Aug 2017) Part II
  5. (28 Aug 2017) Part I