Not enough RAM due to many variables in php array?

Question

PHP

I need to parse several million id users in VK, and then compare them with my list where there are also a lot of users and find the intersection. I did this and got an error that there is not enough memory. The maximum in the settings the script can consume 126 MB, I need to keep within the lower consumption, is it possible? You can give an example of how such services work - stats.ecotime.me/comparisons, at least in words. After all, there are many users who want to make an intersection, and the memory is not infinite.

Answer 1

Instead of a regular array, you can use SplFixedArray or even Judy array .
But isn't it better to do it in a database?

Answer 2

Upload data in batches. For example, 1000 pcs. for 1 request.