Approximate functions: How do they work?
This page contains the description for my conference session “Approximate functions: How do they work?”, and links to the slide deck and demo code used in this presentation.
Description
| Target audience | Experienced database developers and DBAs, plus all curious geeks. |
| Short description | When a close approximation is good enough, “Approximate Query Processing” can save you a lot of performance. But how? Find out by attending this internals deep dive session! |
| Duration | The ideal length for this session is 60 – 75 minutes. |
| Full abstract | Sometimes, a close approximation is good enough. And sometimes, a close approximation is a lot faster. Microsoft has introduced “Approximate Query Processing” (the APPROX_COUNT_DISTINCT and APPROX_PERCENTILE functions) to give you exactly that benefit when you don’t need exact answers.
But do you have a good response when you propose to use this function and your manager asks you to explain how they work first? Or is your only option to claim “black magic by smart Microsoft engineers”? The algorithms used are not a secret. HyperLogLog and KLL Sketch. And now you most likely know exactly as much as you already knew before. And when you google for those terms … you end up with a headache. Time to join me for a session where I explain the black magic in the simplest possible terms, so that you can then explain it to your manager! |
Resources
Click here to download a ZIP file containing the slide deck and demo code used in this presentation.
(Note: my presentations tend to evolve over time, so the slide deck, demo code, and recording linked here may be different from what you saw in a live delivery; and future live deliveries might improve further).