Coding4Performance 1: Text Builder

As NAV and Business Central evolves user tasks become more complex and BC becomes more powerful to solve this tasks. But this happens often with cost in performance. Even Microsoft published a (very good) article about how to improve performance in BC.

I do mainly concentrate on the developer aspect of this article and in this post especially on the TextBuilder Data Type.

So it is described that working with this Datatype instead of gluing strings with += together is much more efficient. But how much is much more?

To prove this huge performance boost I created a small test codeunit and run some loops.

The first loop adds 100.000 times a ‘a’ into a text variable. The second one uses the TextBuilder variable to do the same. Here is the result:

I repeated the test with 10 million times ‘a’. I canceled the test with the text variable after more than 4 hours. Interesting here is, that it takes longer than ~ 500 seconds although the test with 10 million loops has exactly 100 times more loops. Take a closer look at the article about TextBuilder in the MS Docs. There is explained that the normal text variable needs to reallocate memory for the whole string each time you add a string to it. This means that the 10 million a’s take exponentially more time to process than the 100.000 a’s.

But with the TextBuilder we even have a few more functions that come in handy. But how do they perform? (Note: There are still more functions for you to discover by yourself!)

AppendLine() is exactly as fast as adding only text!

Replace(): Yes that is right! We do have a replace which can replace without any length restriction like ConvertStr() has. To test this I added 10 million times ‘abc’ and then replaced ‘bc’ with ‘a’:

Still only 6 seconds!

In conclusion I think that the new TextBuilder can really speed things up!

But: My examples and test are quite provoking the bad performance of normal text variables. That is because in normal examples from daily work, you would probably not see any difference.

Anyway I think that I will use the TextBuilder in my daily work more often, just for the handy functions it has.