Você deve redefinir a sequência no banco de dados antes de qualquer inserção usando valores gerados automaticamente. É altamente dependente da tabela DDL. Existem dois exemplos para o autogen do ID mais usado:
/*
-- Be careful with these 3 lines if you already have such objects in the your DB
drop table if exists t1;
drop table if exists t2;
drop sequence if exists seq_t2_id;
*/
-- Using serial type for ID
create table t1 (t1_id serial, t1_name char varying);
insert into t1 (t1_id, t1_name) values (22, 'aaa');
select setval(pg_get_serial_sequence('t1', 't1_id'), (select max(t1_id) from t1)); -- Reset serial value
insert into t1 (t1_name) values ('bbb');
select * from t1;
-- Using sequence to generate IDs
create sequence seq_t2_id;
create table t2(t2_id bigint default nextval('seq_t2_id'), t2_name char varying);
insert into t2(t2_id, t2_name) values (22, 'aaa');
select setval('seq_t2_id', (select max(t2_id) from t2)); -- Update sequence
insert into t2 (t2_name) values ('bbb');
select * from t2;
