duplicate key value violates unique constraint already exists postgresql code example

Example 1: To ignore duplicate keys during 'copy from' in postgresql

create temp table tmp_table on commit drop as select * from brand with no data;
copy tmp_table (name,slug) from '/var/lib/postgresql/data/Brands.csv' DELIMITER ',' csv header;
insert into brand select distinct on (slug) * from tmp_table;

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.