I recently created a SQL dump of a database behind a Django project, and after cleaning the SQL up a little bit was able to restore the DB and all of the data. The problem was the sequences were all mucked up. I tried adding a new user and generated the Python error IntegrityError: duplicate key violates unique constraint.

Naturally I figured my SQL dump didn't restart the sequence. But it did:

DROP SEQUENCE "auth_user_id_seq" CASCADE;
CREATE SEQUENCE "auth_user_id_seq" INCREMENT 1 START 446 MAXVALUE 9223372036854775807 MINVALUE 1 CACHE 1;
ALTER TABLE "auth_user_id_seq" OWNER TO "db_user";

I figured out that a repeated attempt at creating a user (or any new row in any table with existing data and such a sequence) allowed for successful object/row creation. That solved the pressing problem.

But given that the last user ID in that table was 446 - the same start value in the sequence creation above - it looks like Postgresql was simply trying to start creating rows with that key.

Does the SQL dump provide the wrong start key by 1? Or should I invoke some other command to start sequences after the given start ID? Keenly curious.