I think you would have to decide what constitutes uniquely identifiable by assuming that a number of places from the right make it uniquely identifiable. I think this is folly but the way you would do that is something like this:

SELECT RIGHT(uuid_column_name::text, 7) as your_truncated_uuid FROM table_with_uuid_column;

That takes the 7 places from the right of the text value of the uuid column.

No, there is not. A UUID is a hex representation of a 120 bit random number, at least the v4 variant. It's not even guaranteed to be unique though it likely is.

You have a few options to implement this:

• shave off characters and hope you don't introduce a collision. For instance, if you make d8366842-8c1d-4a31-a4c0-f1765b8ab108 d8366842, you have 16**8 possible combinations, or 4,294,967,296. how likely is your dataset to have a collision with 4.2 billion (2**32) possibilities? Perhaps you can add 8c1d back in to make it 16**12 or 28,147,497,6710,656 possibilities.
• process and hash each row looking for collisions and recursively increase the frame of characters until no collisions are found, or hash every possible permutation.

That all said, another idea is to use ints and not uuids and then to use http://hashids.org/ which has a plugin for PostgreSQL. This is the method YouTube uses afaik.