HyperLogLog
Hyperloglog is like counting how many different things you see in a big pile, but instead of having to look at every thing and count them one by one, you only have to look at a small sample of things and guess how many different things there are based on that sample.
It's like counting how many different colored candies are in a jar without having to count every single one. You can take a small handful of candies and guess how many different colors there are in the jar based on that sample.
Hyperloglog is really good at estimating the number of different things in a huge pile, like how many different words are in a book or how many different users are on a website. It uses some fancy math to make really good guesses without having to look at every single thing.
It's like counting how many different colored candies are in a jar without having to count every single one. You can take a small handful of candies and guess how many different colors there are in the jar based on that sample.
Hyperloglog is really good at estimating the number of different things in a huge pile, like how many different words are in a book or how many different users are on a website. It uses some fancy math to make really good guesses without having to look at every single thing.