The downside of being too fast

Today when I was tracking down some changes, I came across this commit comment

The bugfix for COM-xxxx seems to make the importing
of metafields too fast and causing too many events raised,
potentially flood the event system. This avoids raising the events

Who wrote this? Me, almost 5 years ago. I did have a chuckle in my head, for my younger self being brutally honest (I was the one who fixed the original bug, so I was responsible for making it “too fast”.). Because it was sending too many events in a short time, the event system was overwhelmed and some other events (like cache invalidation of other parts) did not get through.

Well, the bug fix makes it even faster by reducing the number of events raised. In the end, everyone was happy.

Moral of the story:

  • The system can only be as fast as the slowest component. Keep that in mind when you put your effort. In most cases, the slowest part is where you should spend your time.
  • It is important to validate any optimization is end-to-end. Faster is not always better if some other parts (that part) could not keep up with this part becomes unexpectedly faster.
  • You can’t predict everything, something will happen in the most unexpected way. Move fast, break things, learn from it, fix it. Rinse and Repeat.