Use Sequence created by Flyway in JPA - postgresql

Question

I'm using a Spring Boot 2 / Flyway / Postgres setup.
I want to achieve to let Flyway create a table with a sequence for automatic key iteration. JPA should recognize the sequence and use it.
I let Flyway execute a PostgreSQL script:
CREATE SEQUENCE config_id_seq;
CREATE TABLE config
(
ID BIGINT NOT NULL PRIMARY KEY DEFAULT nextval('config_id_seq'),
DESCRIPTION VARCHAR(500)
);
And this is the Entity definition:
#Entity
#Table(name = "config")
public class Config {
#Id
#SequenceGenerator(name = "config_id_sequence", sequenceName = "config_id_seq")
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "config_id_sequence")
#Column(name = "id")
private long id;
#Column(name = "description")
private String description;
On start up the following errors are thrown:
Caused by: org.postgresql.util.PSQLException: ERROR: relation "config_id_seq" already exists
Caused by: org.postgresql.util.PSQLException: ERROR: cannot change sequence "config_id_seq"
My interpretation is that Flyway successfully executed the script and created a sequence. But JPA wants to create the sequence afterwards and fails because it already exists. Please, correct me if I'm wrong here.
Now how can I configure JPA to reuse the existing sequence, if this is possible?

Answer 1

We need to set spring.jpa.hibernate.ddl-auto property to none or you can skip this property so that spring does not create database objects on its own.
If we are using a flyway then we should give the responsibility of database objects creation to flyway only i.e create all database objects with flyway scripts only like tables and sequence.
Specifying GeneratedValue says for JPA to use a sequence, retrieve the next value itself, and then use that in the INSERT.
But make sure you have the same configuration that you mentioned on entity class and flyway script.