JPA AttributeConverter заставляет hibernate генерировать инструкции обновления для всей таблицы в транзакции ⇐ JAVA

[Anonymous]

Весь код в этом посте можно найти здесь:
https://github.com/cuipengfei/gs-access ... r/complete

Вы можете запустить этот тест, чтобы воспроизвести проблему:
https://github.com/cuipengfei/gs-access ... java/hello /T1ServiceTest.java

У меня есть модель домена:

Код: Выделить всё

@Entity
@Table(name = "t1", schema = "test")
public class T1 extends BaseEntity {

@Column(nullable = false)
private UUID someField;

@Column()
private ZonedDateTime date;

public T1(UUID someField, ZonedDateTime date) {
this.someField = someField;
this.date = date;
}
}

В нем есть поле с типом ZonedDateTime, поэтому у меня есть конвертер для преобразования его в отметку времени sql:

Код: Выделить всё

@Converter(autoApply = true)
public class ZonedDateTimeAttributeConverter
implements AttributeConverter {

@Override
public Timestamp convertToDatabaseColumn(ZonedDateTime entityValue) {
return (entityValue == null) ? null :
valueOf(entityValue.withZoneSameInstant(of("UTC")).toLocalDateTime());
}

@Override
public ZonedDateTime convertToEntityAttribute(Timestamp databaseValue) {
return (databaseValue == null) ? null : databaseValue.toLocalDateTime().atZone(
of("UTC"));
}
}

Когда я пытаюсь создать много T1 в такой транзакции:

Код: Выделить всё

@Service
public class T1Service {
private static final Logger log = LoggerFactory.getLogger(T1Service.class);

@Autowired
T1Repository t1Repository;

@Transactional
public void insertMany() {
for (int i = 0; i < 1000;  i++) {
log.info("!!! " + (i + 1) + "th item start");

UUID randomUUID = UUID.randomUUID();
T1 foundT1 = tryToFindExistingT1(randomUUID);//certainly won't find

if (foundT1 == null) {
log.info("t1 not found");
ZonedDateTime date = now();
//date = null;
//if you enable the line above, there won't be any update statements anymore
//and find will also become faster
T1 t1 = new T1(randomUUID, date);
saveT1(t1);
}

log.info("!!! " + (i + 1) + "th item finished");
log.info("====================================");
}
}

private T1 tryToFindExistingT1(UUID someField) {
long start = currentTimeMillis();
T1 t1Id = t1Repository.findBySomeField(someField);
//as nth item increases, the line above will become very very slow
//and also, there will be more and more update statements
//but if you set date of t1 to null, update statement will disappear and it'll not be slow
log.info("find took: " + (currentTimeMillis() - start) + " milliseconds");
return t1Id;
}

private T1 saveT1(T1 t1) {
long start = currentTimeMillis();
T1 savedT1 = t1Repository.save(t1);
log.info("save took: " + (currentTimeMillis() - start) + " milliseconds");
return savedT1;
}

}

В режиме гибернации будут созданы операторы обновления для всей таблицы t1.

Вот журнал для сначала несколько раундов цикла for:

Код: Выделить всё

2017-03-20 17:51:54.039  INFO 74789 --- [           main] hello.T1Service                          : !!! 1th item start
2017-03-20 17:51:54.052  INFO 74789 --- [           main] o.h.h.i.QueryTranslatorFactoryInitiator  : HHH000397: Using ASTQueryTranslatorFactory
Hibernate: select t1x0_.id as id1_0_, t1x0_.date as date2_0_, t1x0_.some_field as some_fie3_0_ from test.t1 t1x0_ where t1x0_.some_field=?
2017-03-20 17:51:54.154  INFO 74789 --- [           main] hello.T1Service                          : find took: 114 milliseconds
2017-03-20 17:51:54.154  INFO 74789 --- [           main] hello.T1Service                          : t1 not found
2017-03-20 17:51:54.177  INFO 74789 --- [           main] hello.T1Service                          : save took: 15 milliseconds
2017-03-20 17:51:54.177  INFO 74789 --- [           main] hello.T1Service                          : !!! 1th item finished
2017-03-20 17:51:54.177  INFO 74789 --- [           main] hello.T1Service                          : ====================================
2017-03-20 17:51:54.177  INFO 74789 --- [           main] hello.T1Service                          : !!! 2th item start
Hibernate: insert into test.t1 (date, some_field, id) values (?, ?, ?)
Hibernate: update test.t1 set date=?, some_field=? where id=?
Hibernate: select t1x0_.id as id1_0_, t1x0_.date as date2_0_, t1x0_.some_field as some_fie3_0_ from test.t1 t1x0_ where t1x0_.some_field=?
2017-03-20 17:51:54.194  INFO 74789 --- [           main] hello.T1Service                          : find took: 17 milliseconds
2017-03-20 17:51:54.194  INFO 74789 --- [           main] hello.T1Service                          : t1 not found
2017-03-20 17:51:54.195  INFO 74789 --- [           main] hello.T1Service                          : save took: 1 milliseconds
2017-03-20 17:51:54.195  INFO 74789 --- [           main] hello.T1Service                          : !!! 2th item finished
2017-03-20 17:51:54.195  INFO 74789 --- [           main] hello.T1Service                          : ====================================
2017-03-20 17:51:54.195  INFO 74789 --- [           main] hello.T1Service                          : !!! 3th item start
Hibernate: insert into test.t1 (date, some_field, id) values (?, ?, ?)
Hibernate: update test.t1 set date=?, some_field=? where id=?
Hibernate: update test.t1 set date=?, some_field=? where id=?
Hibernate: select t1x0_.id as id1_0_, t1x0_.date as date2_0_, t1x0_.some_field as some_fie3_0_ from test.t1 t1x0_ where t1x0_.some_field=?
2017-03-20 17:51:54.200  INFO 74789 --- [           main] hello.T1Service                          : find took: 4 milliseconds
2017-03-20 17:51:54.200  INFO 74789 --- [           main] hello.T1Service                          : t1 not found
2017-03-20 17:51:54.200  INFO 74789 --- [           main] hello.T1Service                          : save took: 0 milliseconds
2017-03-20 17:51:54.200  INFO 74789 --- [           main] hello.T1Service                          : !!! 3th item finished
2017-03-20 17:51:54.200  INFO 74789 --- [           main] hello.T1Service                          :  ====================================
2017-03-20 17:51:54.200  INFO 74789 --- [           main] hello.T1Service                          : !!! 4th item start
Hibernate: insert into test.t1 (date, some_field, id) values (?, ?, ?)
Hibernate: update test.t1 set date=?, some_field=? where id=?
Hibernate: update test.t1 set date=?, some_field=? where id=?
Hibernate: update test.t1 set date=?, some_field=? where id=?
Hibernate: select t1x0_.id as id1_0_, t1x0_.date as date2_0_, t1x0_.some_field as some_fie3_0_ from test.t1 t1x0_ where t1x0_.some_field=?
2017-03-20 17:51:54.209  INFO 74789 --- [           main] hello.T1Service                          : find took: 9 milliseconds
2017-03-20 17:51:54.209  INFO 74789 --- [           main] hello.T1Service                          : t1 not found
2017-03-20 17:51:54.210  INFO 74789 --- [           main] hello.T1Service                          : save took: 1 milliseconds
2017-03-20 17:51:54.210  INFO 74789 --- [           main] hello.T1Service                          : !!! 4th item finished
2017-03-20 17:51:54.210  INFO 74789 --- [           main] hello.T1Service                          : ====================================

Как видно из журнала, в спящем режиме будет генерироваться все больше и больше операторов обновления.

Это похоже, что количество операторов обновления всегда равно количеству строк T1, ожидающих фиксации.

Теперь, если я удалю преобразователь, эта проблема исчезнет. .

Я могу использовать библиотеку hibernate-java8 вместо этого конвертера, чтобы добиться того же эффекта, но почему это происходит?

Почему JPA AttributeConverter заставляет спящий режим генерировать инструкции обновления для всей таблицы в транзакции?

Подробнее здесь: https://stackoverflow.com/questions/429 ... hole-table