What is the best type of index to choose for the following data?

Question

PostgreSQL

I have a column with statuses: success, failed, pending.
Question - what type of an index it is better to select?

Answer 1

Can you imagine walking through a binary tree in which you need to select a third of the rows in the table? It will, of course, be faster than a full scan - but there will be much more benefit from an index on some more distinct field or combination of fields.