SQL Server Int or BigInt database table Ids

Question

I am writing a new program and it will require a database (SQL Server 2008). Everything I am running now for the system is 64-bit, which brings me to this question. For all

Answer 1

Other people already gave compelling answers for 32-bit IDs.

For some applications 64-bit IDs do make more sense.

If you want to guarantee that IDs are unique across a cluster of databases - 63-bits for IDs can be very convenient. With 32 bits it's very difficult to distribute generation of IDs across servers in a cluster; or across data centers. While with 64 bits you have enough room to play with that you can conveniently generate IDs across servers without locking and still guarantee uniqueness.

For example see Twitter Snowflake, and Instagram Engineering's blog post on "Sharding & IDs at Instagram". Both provide good reasons why 63 or 64 bits make more sense for their IDs than 32-bit counters.