Blogmark

To avoid contention on a single high-write counter column, you can create a generic slotted counter table with polymorphic associations to anything that needs counting. Then to update the count, you increment the count in one of one hundred random slots. You can either sum the counts for a specific record and type to get the count, or you can have a process to roll up the count periodically and store it nearer to the original record.

I wonder what heuristics you could use to scale the number of slots you use for a given entity. That way for a relatively low-update entity, you spread the counts over, say, 3 counter slots. And with a very high-update entity, you spread it across, say, 50 or 100 slots.