ChaiPoha

System Design - unique usernames

Problem: Keep usernames unique Single DB: pretty straight forward to have unique check on the column itself.

What solutions can work for disturbuted systems?

17mo ago

its_a_me_mario

If you just want to check if the username already exists in DB use a bloom filter. If you want to store it as well, use a DHT.

ChaiPoha

Razorpay17mo

Sounds good. How will we store these? Reconstruction of bloom filters can be lengthy too.

its_a_me_mario

Stealth17mo

In a sharded database. Use consistent hashing to know what’s stored in which shard.
You don’t have to do these from scratch pretty sure aws and other cloud providers have prebuilt services for these type of problems.

Twitter

Stealth17mo

Please don't make this another stack overflow.

FamousCoil13

Stealth17mo

Have a username database(not necessarily seperate from a current existing one) which stores username against a GUID. Then use this GUID as a secondary key everywhere else in database. Make sure uniqueness check is maintained in other databases as well.