https://vladmihalcea.com/postgresql-serial-column-hibernate-identity/
Although convenient, and even suggested in many PostgreSQL book, the SERIAL and BIGSERIAL column types are not a very good choice when using JPA and Hibernate. Using a SEQUENCE generator is a better alternative since the identifier can be generated prior to executing the INSERT statement.
Behind the scenes, the SERIAL and BIGSERIAL column types use a database sequence anyway, so the only difference is that the SEQUENCE generator calls the sequence is a separate database roundtrip. However, this can also be optimized with the pooled and pooled-lo optimizers.
If the database server is close to the application servers and networking is fast, the extra database roundtrip is not going to be a performance bottleneck. For all these reasons, you should prefer using the SEQUENCE generator over IDENTITY no matter if you use PostgreSQL, Oracle or SQL Server.
REFER:
Why To Avoid PostgreSQL (BIG)SERIAL In Batching Inserts Via Hibernate
https://github.com/AnghelLeonard/Hibernate-SpringBoot/tree/master/HibernateSpringBootBatchingAndSerial
https://github.com/AnghelLeonard/Hibernate-SpringBoot/tree/master/HibernateSpringBootBatchInsertsJpaRepository
https://github.com/AnghelLeonard/Hibernate-SpringBoot/tree/master/HibernateSpringBootBatchInsertsEntityManagerBatchPerTransaction
https://www.baeldung.com/jpa-hibernate-batch-insert-update
https://jdbc.postgresql.org/documentation/94/connect.html
https://vladmihalcea.com/9-postgresql-high-performance-performance-tips/
PostgreSQL batch insert - jdbc reWriteBatchedInserts 批量写入 (copy,insert,begin commit,group commit)
https://github.com/digoal/blog/blob/master/201910/20191030_01.md
https://github.com/aruis/mysql_vs_postgresql