Which is the data type to use for storing a firebase uid in postgresql

Question

I want to store the uids generated by firebase auth in a postgres database. As it is not a valid uuid I am not sure which datatype to choose. Mainly I am not sure if I should use a char or a varchar.

Answer 1

I would say use varchar to allow for the uid changing over time. From the Postgres end there is really no difference, see here:

Tip

There is no performance difference among these three types, apart from increased storage space when using the blank-padded type, and a few extra CPU cycles to check the length when storing into a length-constrained column. While character(n) has performance advantages in some other database systems, there is no such advantage in PostgreSQL; in fact character(n) is usually the slowest of the three because of its additional storage costs. In most situations text or character varying should be used instead.

Answer 2

Firebase Authentication UIDs are just strings. The strings don't contain any data - they are just random. A varchar seems appropriate.