duplicate key value violates unique constraint "" (PG::UniqueViolation) code example

Example 1: postgresql resolv duplicate value violates unique constraint

SELECT setval(pg_get_serial_sequence('users', 'id'), coalesce(max(id)+1, 1), false) FROM users;

Example 2: duplicate key value violates unique constraint "pg_type_typname_nsp_index"

I was reading this. It seems this error rises when you are creating/updating the same table with parallel processing. I understand it depends because of this (as explained on the google group discussion).

So I think it depend from PostgreSQL itself and not from the connection driver or the module used for the multiprocessing.

Well, Actually, the only way I found to solve this is to create chunks big enough to have back a writing process slower than the calculation itself. With bigger chunks this error doesn't rise.