hibernate - JPA/hibernate : select currval on non existing sequence/relation

Question

我在使用 JPA/Hibernate 时遇到了一个令人困惑的问题:将值插入表后，对不存在的关系/序列执行 select currval() 。我有两个类似的案例，一个有效，另一个无效。

这是第一个非工作版本。

实体:

@Entity
@Table(name = "meter")
@Data
@EqualsAndHashCode(callSuper = true)
public class Meter extends AbstractTimestampEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "meter_id")
    private Long meterId;

    @Column(name = "meter_id_str")
    private String meterIdStr;

    @Column(name = "contract_id")
    private Long contractId;

    @Column(name = "user_id")
    private Long userId;

    @Column(name = "com_id")
    private String comId;

    @Column(name = "is_active")
    private Boolean isActive;   
}

飞路脚本:

CREATE SEQUENCE meter_seq;
CREATE TABLE IF NOT EXISTS meter (
  id           BIGINT NOT NULL DEFAULT nextval('meter_seq'),
  meter_id     BIGINT,
  meter_id_str VARCHAR(20),
  contract_id  BIGINT,
  user_id      BIGINT,
  com_id       VARCHAR(50),
  is_active    BOOLEAN,
  created_at   BIGINT,
  modified_at  BIGINT,
  CONSTRAINT pk_meter PRIMARY KEY (id)
);
ALTER SEQUENCE meter_seq OWNED BY meter.id;

服务:

@Override
@Transactional
public void updateUser(UserDTO userDTO, ContractDTO contractDTO, MeterDTO meterDTO) {
    String meterIdStr = meterDTO.getMeterId();
    long uid = userDTO.getId();
    long cid = contractDTO.getId();
    long mid = meterDTO.getId();
    boolean isActive = meterDTO.isActive();

    log.debug("Updating meter state: {}, isActive: {}, contractId: {}, userId: {}", mid, isActive, cid, uid);

    Meter meter = this.meterRepository.find(uid, cid, meterIdStr);
    if (meter == null) {
        log.debug("No meter found, creating new meter.");
        meter = new Meter();
        meter.setMeterId(mid);
        meter.setMeterIdStr(meterIdStr);
        meter.setContractId(cid);
        meter.setUserId(uid);
        meter.setIsActive(true);
        this.meterRepository.save(meter);
    } else {
        if (isActive != meter.getIsActive()) {
            meter.setIsActive(isActive);
            this.meterRepository.save(meter);
            this.cacheService.evict(CacheNames.METER,
                    new SimpleKey(meter.getMeterIdStr(), meter.getComId()).toString());

            // remove meter from monitoring if it is not active any longer
            if (!isActive) {
                String key = String.format("%d-%d-%d", uid, cid, mid);
                this.boundHashOperations.delete(key);
            }
        }
    }

    log.debug("Done");
}

插入新的 Meter 时总是出现错误(在服务类中的 this.meterRepository.save() 行中):

2018-05-23 06:42:21.303 TRACE - [-enerContainer-4]            o.h.e.j.i.JdbcCoordinatorImpl : Starting after statement execution processing [ON_CLOSE]
2018-05-23 06:42:21.303 DEBUG - [-enerContainer-4]                          o.hibernate.SQL : select currval('meter_data_receiver.meter_id_seq')
2018-05-23 06:42:21.303 TRACE - [-enerContainer-4]   o.h.r.j.i.ResourceRegistryStandardImpl : Registering statement [HikariProxyPreparedStatement@75642772 wrapping select currval('meter_data_receiver.meter_id_seq')]
2018-05-23 06:42:21.304 ERROR - [-enerContainer-4]             o.h.e.j.s.SqlExceptionHelper : FEHLER: Relation „meter_data_receiver.meter_id_seq“ existiert nicht

排名:16

没有序列/关系“meter_data_receiver.meter_id_seq”。

另一种情况类似，但在这里我可以在日志中看到以下消息:

2018-05-23 06:42:21.345 DEBUG - [RedisMessageLis]          o.h.i.IdentifierGeneratorHelper : Natively generated identity: 2

因此，在这种情况下，ID 似乎是在插入操作后从数据库中获取的，而在第一种情况下，对不存在的序列/关系执行了额外的 select 。

我不知道为什么 Hibernate 认为它可以通过查询序列来获取第一个案例的 ID...

Answer 1

好的，我已从配置中删除了选项 properties.hibernate.temp.use_jdbc_metadata_defaults: false，现在它似乎可以工作。

我不确定为什么我首先添加此选项，我认为有一个警告建议我应该添加它......