Postgres + EJB3预分配大小错误

Question

我对postgres和jpa中的顺序有问题。

Caused by: javax.persistence.EntityExistsException:
Exception Description: The sequence named [shp_users_seq] is setup incorrectly.  Its increment does not match its pre-allocation size.
        at org.eclipse.persistence.internal.jpa.EntityManagerImpl.persist(EntityManagerImpl.java:443)
        at com.sun.enterprise.container.common.impl.EntityManagerWrapper.persist(EntityManagerWrapper.java:269)
        at base.data.provider.beans.session.DAOImpl.createUser(DAOImpl.java:18)

Answer 1

规则是:序列的增量大小是jpa中allocationSize的值:我有这样的设置:这是错误的：

@SequenceGenerator(name = "User_Seq_Gen", 
                   sequenceName = "shp_users_seq", allocationSize=999)

根据以下内容进行更正：

@SequenceGenerator(name = "User_Seq_Gen", 
                   sequenceName = "shp_users_seq" ,allocationSize=1)

因为序列的增量大小是1：

 shopper=> \d shp_users_seq;
        Sequence "public.shp_users_seq"
    Column     |  Type   |        Value
---------------+---------+---------------------
 sequence_name | name    | shp_users_seq
 last_value    | bigint  | 1
 start_value   | bigint  | 1
 increment_by  | bigint  | 1
 max_value     | bigint  | 9223372036854775807
 min_value     | bigint  | 1
 cache_value   | bigint  | 1
 log_cnt       | bigint  | 0
 is_cycled     | boolean | f
 is_called     | boolean | t

Answer 2

尝试将序列的起始值设置为至少与用于@SequenceGenerator注释的属性allocationSize的大小相同的值。

 CREATE SEQUENCE seq_name
 ...
 START WITH 100;

有关这方面的详细信息，请参阅http://dev.eclipse.org/mhonarc/lists/eclipselink-users/msg03461.html。