Auto increment in MongoDB to store sequence of Unique User ID

est picture est · Dec 5, 2011 · Viewed 124.3k times · Source

I am making a analytics system, the API call would provide a Unique User ID, but it's not in sequence and too sparse.

I need to give each Unique User ID an auto increment id to mark a analytics datapoint in a bitarray/bitset. So the first user encounters would corresponding to the first bit of the bitarray, second user would be the second bit in the bitarray, etc.

So is there a solid and fast way to generate incremental Unique User IDs in MongoDB?

Answer

expert picture expert · Jan 21, 2013

As selected answer says you can use findAndModify to generate sequential IDs.

But I strongly disagree with opinion that you should not do that. It all depends on your business needs. Having 12-byte ID may be very resource consuming and cause significant scalability issues in future.

I have detailed answer here.