Spring Data JPA開(kāi)啟批量更新時(shí)樂(lè)觀鎖失效問(wèn)題的解決方法
更新時(shí)間：2024年07月04日 10:01:26 作者：TechGenius
樂(lè)觀鎖的基本思想是,認(rèn)為在大多數(shù)情況下,數(shù)據(jù)訪問(wèn)不會(huì)導(dǎo)致沖突,因此,樂(lè)觀鎖允許多個(gè)事務(wù)同時(shí)讀取和修改相同的數(shù)據(jù),而不進(jìn)行顯式的鎖定,本文給大家介紹了Spring Data JPA開(kāi)啟批量更新時(shí)樂(lè)觀鎖失效問(wèn)題的解決方法,需要的朋友可以參考下
樂(lè)觀鎖機(jī)制
什么是樂(lè)觀鎖？
樂(lè)觀鎖的基本思想是，認(rèn)為在大多數(shù)情況下，數(shù)據(jù)訪問(wèn)不會(huì)導(dǎo)致沖突。因此，樂(lè)觀鎖允許多個(gè)事務(wù)同時(shí)讀取和修改相同的數(shù)據(jù)，而不進(jìn)行顯式的鎖定。在提交事務(wù)之前，會(huì)檢查是否有其他事務(wù)對(duì)該數(shù)據(jù)進(jìn)行了修改。如果沒(méi)有沖突，則提交成功；如果發(fā)現(xiàn)沖突，就需要回滾并重新嘗試。
樂(lè)觀鎖通常使用版本號(hào)或時(shí)間戳來(lái)實(shí)現(xiàn)。每個(gè)數(shù)據(jù)項(xiàng)都會(huì)包含一個(gè)表示當(dāng)前版本的標(biāo)識(shí)符。在讀取數(shù)據(jù)時(shí)，會(huì)將版本標(biāo)識(shí)符保存下來(lái)。在提交更新時(shí)，會(huì)檢查數(shù)據(jù)的當(dāng)前版本是否與保存的版本匹配。如果匹配，則更新成功；否則，表示數(shù)據(jù)已被其他事務(wù)修改，需要處理沖突。
樂(lè)觀鎖適用于讀操作頻率較高、寫操作沖突較少的場(chǎng)景。它減少了鎖的使用，提高了并發(fā)性能，但需要處理沖突和重試的情況。
樂(lè)觀鎖是一種廣義的思想，不是某一框架或語(yǔ)言特有的。
樂(lè)觀鎖的優(yōu)缺點(diǎn)
優(yōu)點(diǎn)
- 增強(qiáng)吞吐量：由于在事務(wù)持續(xù)時(shí)間的大部分時(shí)間內(nèi)沒(méi)有持有鎖，因此等待時(shí)間最少，吞吐量也是最?的。
- 最小化死鎖：死鎖是一種事務(wù)無(wú)限期地等待其他人鎖定的資源的情況，這種情況的可能性要小得多，因?yàn)閿?shù)據(jù)不會(huì)長(zhǎng)時(shí)間鎖定。
- 更好的可擴(kuò)展性：隨著分布式系統(tǒng)和微服務(wù)架構(gòu)的興起，樂(lè)觀鎖在確保系統(tǒng)能夠有效擴(kuò)展而無(wú)需管理復(fù)雜鎖機(jī)制的開(kāi)銷方面發(fā)揮著關(guān)鍵作用。
缺點(diǎn)
- 沖突管理開(kāi)銷：在沖突頻繁的場(chǎng)景中，管理和解決沖突可能會(huì)占用大量資源。
- 復(fù)雜性：實(shí)現(xiàn)樂(lè)觀鎖需要經(jīng)過(guò)深思熟慮的設(shè)計(jì)，特別是在處理失敗的事務(wù)時(shí)。
- 過(guò)時(shí)數(shù)據(jù)的可能性：由于數(shù)據(jù)在讀取時(shí)未鎖定，因此事務(wù)可能會(huì)使用過(guò)時(shí)或過(guò)時(shí)的數(shù)據(jù)，如果管理不正確，可能會(huì)導(dǎo)致邏輯錯(cuò)誤或不一致。
JPA-樂(lè)觀鎖
概述
JPA（Java Persistence API）協(xié)議對(duì)樂(lè)觀鎖的操作做了規(guī)定：通過(guò)指定@Version字段對(duì)數(shù)據(jù)增加版本號(hào)控制，進(jìn)?在更新的時(shí)候判斷版本號(hào)是否有變化。如果版本沒(méi)有變化則更新成功；如果版本有變化，就會(huì)更新失敗并拋出“OptimisticLockException”異常。我們? SQL 表示?下樂(lè)觀鎖的做法，代碼如下：
SELECT uid, name, version FROM user WHERE id = 1; UPDATE user SET name = 'jack', version = version + 1 WHERE id = 1 AND version = 1;
假設(shè)本次查詢的version=1，在更新操作時(shí)，只要version與上一個(gè)版本相同，就會(huì)更新成功，并且不會(huì)出現(xiàn)互相覆蓋的問(wèn)題，保證了數(shù)據(jù)的原?性。
實(shí)現(xiàn)方法
JPA 協(xié)議規(guī)定，想要實(shí)現(xiàn)樂(lè)觀鎖，可以通過(guò)@Version注解標(biāo)注在某個(gè)字段上?，而此字段需要是可以持久化到DB的字段，并且只?持如下四種類型：
int或Integershort或Shortlong或Longjava.sql.Timestamp
我比較推薦使用Integer類型的字段，語(yǔ)義比較清晰、簡(jiǎn)單。
@Version的作用
該@Version注解用于啟用實(shí)體上的樂(lè)觀鎖，確保數(shù)據(jù)庫(kù)中的數(shù)據(jù)更新不會(huì)出現(xiàn)并發(fā)修改問(wèn)題。當(dāng)實(shí)體中的某個(gè)字段標(biāo)記為@Version時(shí)，JPA 將使用該字段來(lái)跟蹤更改并確保一次只有一個(gè)事務(wù)可以更新特定行。
注意：Spring Data JPA ??有兩個(gè)@Version注解，請(qǐng)使?@javax.persistence.Version，?不是@org.springframework.data.annotation.Version。
它是如何工作的？
每個(gè)用注解標(biāo)記的實(shí)體都@Version將由 JPA 跟蹤其版本。這是基本機(jī)制：
- 初始化：當(dāng)實(shí)體第一次被持久化（保存到數(shù)據(jù)庫(kù)）時(shí)，版本字段（通常是整數(shù)或時(shí)間戳）被設(shè)置為其初始值，通常為零。
- 讀取：稍后獲取實(shí)體時(shí)，JPA 會(huì)從數(shù)據(jù)庫(kù)中檢索當(dāng)前版本。
- 更新：在嘗試更新或刪除實(shí)體時(shí)，JPA 會(huì)根據(jù)實(shí)體的版本檢查數(shù)據(jù)庫(kù)中的當(dāng)前版本。如果版本匹配，則操作繼續(xù)，并且數(shù)據(jù)庫(kù)中的版本增加（用于更新）。
- 沖突：如果版本不匹配，則表明另一個(gè)事務(wù)同時(shí)更新了實(shí)體，導(dǎo)致 JPA 拋出
OptimisticLockException。
項(xiàng)目示例
引入依賴
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <!-- 驅(qū)動(dòng) --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <!-- 數(shù)據(jù)庫(kù)連接池 --> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-dbcp2</artifactId> </dependency>
項(xiàng)目配置
spring:
datasource:
url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&useSSL=false
username: root
password: root
jpa:
database: mysql
database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
show-sql: true
hibernate:
ddl-auto: update # 一般使用update
# create: 每次運(yùn)行程序時(shí)，都會(huì)重新創(chuàng)建表，故而數(shù)據(jù)會(huì)丟失
# create-drop: 每次運(yùn)行程序時(shí)會(huì)先創(chuàng)建表結(jié)構(gòu)，然后待程序結(jié)束時(shí)清空表
# upadte: 每次運(yùn)行程序，沒(méi)有表時(shí)會(huì)創(chuàng)建表，如果對(duì)象發(fā)生改變會(huì)更新表結(jié)構(gòu)，原有數(shù)據(jù)不會(huì)清空，只會(huì)更新（推薦使用）
# validate: 運(yùn)行程序會(huì)校驗(yàn)數(shù)據(jù)與數(shù)據(jù)庫(kù)的字段類型是否相同，字段不同會(huì)報(bào)錯(cuò)
# none: 禁用DDL處理
open-in-view: false
properties:
hibernate:
jdbc: # 開(kāi)啟批量更新/寫入
batch_size: 50
batch_versioned_data: true
order_inserts: true
order_updates: true
實(shí)體添加@Version
User實(shí)體增加字段version，并添加注解@Version。當(dāng)然，數(shù)據(jù)庫(kù)也要加上version字段。
@Entity
@Table(name = "TEST_USER")
public class User {
// ......
@Version
private Integer version;
// ......
}
創(chuàng)建UserInfoRepository
創(chuàng)建UserInfoRepository，?便進(jìn)?DB操作
public interface UserInfoRepository extends JpaRepository<User, Long> {}
創(chuàng)建 UserInfoService
創(chuàng)建 UserInfoService，?來(lái)模擬Service的復(fù)雜業(yè)務(wù)邏輯。
public interface UserService {
/**
* 根據(jù) UserId 產(chǎn)?的?些業(yè)務(wù)計(jì)算邏輯
*/
User calculate(Long userId);
}
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserRepository userRepository;
@Override
@Transactional
public User calculate(Long userId) {
User user = repository.getById(userId);
// 模擬復(fù)雜的業(yè)務(wù)計(jì)算邏輯耗時(shí)操作；
try {
TimeUnit.SECONDS.sleep(2L);
} catch (InterruptedException ignored) {
}
user.setAge(user.getAge() + 1);
return userRepository.saveAndFlush(user);
}
}
其中，我們通過(guò) @Transactional 開(kāi)啟事務(wù)，并且在查詢?法后?模擬復(fù)雜業(yè)務(wù)邏輯，?來(lái)呈現(xiàn)多線程的并發(fā)問(wèn)題。
測(cè)試方法
@ExtendWith(SpringExtension.class)
@DataJpaTest
@ComponentScan(basePackageClasses = UserServiceImpl.class)
class UserServiceTest {
@Autowired
private UserService userService;
@Autowired
private UserRepository userRepository;
@Test
void testVersion() {
// 加?條數(shù)據(jù)
User user1 = userRepository.save(User.builder().age(20).name("zzn").build());
// 驗(yàn)證?下數(shù)據(jù)庫(kù)??的值
Assertions.assertEquals(0, user1.getVersion());
Assertions.assertEquals(20, user1.getAge());
userService.calculate(user1.getId());
// 驗(yàn)證?下更新成功的值
User user2 = userRepository.getById(user1.getId());
Assertions.assertEquals(1, user2.getVersion());
Assertions.assertEquals(21, user2.getAge());
}
@SneakyThrows
@Test
@Rollback(false)
@Transactional(propagation = Propagation.NEVER)
void testVersionException() {
// 加?條數(shù)據(jù)
userRepository.save(User.builder().age(20).name("zzn").build());
// 模擬多線程執(zhí)?兩次
new Thread(() -> userService.calculate(1L)).start();
TimeUnit.SECONDS.sleep(1L);
// 如果兩個(gè)線程同時(shí)執(zhí)?會(huì)發(fā)?樂(lè)觀鎖異常；
Exception exception = Assertions.assertThrows(ObjectOptimisticLockingFailureException.class,
() -> userService.calculate(1L));
log.info("error info:", exception);
}
}
從上?的測(cè)試得到的結(jié)果中，我們執(zhí)?testVersion()，會(huì)發(fā)現(xiàn)在 save 的時(shí)候， Version會(huì)?動(dòng) +1，第?次初始化為 0；update 的時(shí)候也會(huì)附帶 Version 條件，我們通過(guò)下圖的 SQL，也可以看到 Version 的變化。
?當(dāng)?我們調(diào)?testVersionException()測(cè)試?法的時(shí)候，利?多線程模擬兩個(gè)并發(fā)情況，會(huì)發(fā)現(xiàn)兩個(gè)線程同時(shí)取到了歷史數(shù)據(jù)，并在稍后都對(duì)歷史數(shù)據(jù)進(jìn)?了更新。
由此你會(huì)發(fā)現(xiàn)，第?次測(cè)試的結(jié)果是樂(lè)觀鎖異常，更新不成功。
通過(guò)?志?會(huì)發(fā)現(xiàn)，兩個(gè)SQL同時(shí)更新的時(shí)候，Version是?樣的，是它導(dǎo)致了樂(lè)觀鎖異常。
注意：樂(lè)觀鎖異常不僅僅是同?個(gè)?法多線程才會(huì)出現(xiàn)的問(wèn)題，我們只是為了?便測(cè)試?采?同?個(gè)?法；不同的?法、不同的項(xiàng)?，都有可能導(dǎo)致樂(lè)觀鎖異常。樂(lè)觀鎖的本質(zhì)是 SQL 層?發(fā)?的，和使?的框架、技術(shù)沒(méi)有關(guān)系。
問(wèn)題描述
一句廢話：正常情況下，一切正常！
運(yùn)行環(huán)境
Java：1.8.0 SpringBoot：2.3.12.RELEASE Spring Data JPA：2.3.9.RELEASE Hibernate：5.4.32.Final Database Driver：ojdbc6 11.2.0.3 Database Platform：Oracle 10g
問(wèn)題現(xiàn)象
上述代碼示例運(yùn)行在MySQL數(shù)據(jù)庫(kù)上，一切正常，但是切換到Oracle數(shù)據(jù)庫(kù)時(shí)，不開(kāi)啟批量更新模式時(shí)，也符合預(yù)期，但是開(kāi)啟批量更新模式時(shí)，不符合預(yù)期：并發(fā)更新同一實(shí)體時(shí)，未拋出
ObjectOptimisticLockingFailureException異常。
| 數(shù)據(jù)庫(kù)類型 | 開(kāi)啟批量 | 不開(kāi)啟批量 |
|---|---|---|
| Oracle | 不生效 | 生效 |
| MySQL | 生效 | 生效 |
批量模式下，樂(lè)觀鎖異常棧：
Caused by: org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1; statement executed: update test_user set update_time=?, version=?, remark=? where user_id=? and version=? at org.hibernate.jdbc.Expectations$BasicExpectation.checkBatched(Expectations.java:67) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.jdbc.Expectations$BasicExpectation.verifyOutcome(Expectations.java:54) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.checkRowCounts(BatchingBatch.java:151) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.performExecution(BatchingBatch.java:126) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.doExecuteBatch(BatchingBatch.java:106) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.jdbc.batch.internal.AbstractBatchImpl.execute(AbstractBatchImpl.java:148) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.executeBatch(JdbcCoordinatorImpl.java:198) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:633) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.spi.ActionQueue.lambda$executeActions$1(ActionQueue.java:478) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at java.util.LinkedHashMap.forEach(LinkedHashMap.java:676) ~[?:1.8.0_73] at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:475) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:344) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:40) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:99) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1362) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1349) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_73] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_73] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_73] at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_73] at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:314) ~[spring-orm-5.2.22.RELEASE.jar:5.2.22.RELEASE] at com.sun.proxy.$Proxy156.flush(Unknown Source) ~[?:?] at org.springframework.data.jpa.repository.support.SimpleJpaRepository.flush(SimpleJpaRepository.java:601) ~[spring-data-jpa-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.jpa.repository.support.SimpleJpaRepository.saveAndFlush(SimpleJpaRepository.java:570) ~[spring-data-jpa-2.3.9.RELEASE.jar:2.3.9.RELEASE] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_73] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_73] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_73] at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_73] at org.springframework.data.repository.core.support.ImplementationInvocationMetadata.invoke(ImplementationInvocationMetadata.java:72) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:382) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:205) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:550) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:155) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:130) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367) ~[spring-tx-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118) ~[spring-tx-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.2.22.RELEASE.jar:5.2.22.RELEASE] ... 109 more
非批量模式下，樂(lè)觀鎖異常棧：
Caused by: org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) : [com.esunny.option.domain.user.User#990] at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:2649) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3492) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:3355) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3769) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:201) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:604) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.engine.spi.ActionQueue.lambda$executeActions$1(ActionQueue.java:478) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at java.util.LinkedHashMap.forEach(LinkedHashMap.java:676) ~[?:1.8.0_73] at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:475) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:344) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:40) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:99) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1362) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1349) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_73] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_73] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_73] at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_73] at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:314) ~[spring-orm-5.2.22.RELEASE.jar:5.2.22.RELEASE] at com.sun.proxy.$Proxy156.flush(Unknown Source) ~[?:?] at org.springframework.data.jpa.repository.support.SimpleJpaRepository.flush(SimpleJpaRepository.java:601) ~[spring-data-jpa-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.jpa.repository.support.SimpleJpaRepository.saveAndFlush(SimpleJpaRepository.java:570) ~[spring-data-jpa-2.3.9.RELEASE.jar:2.3.9.RELEASE] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_73] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_73] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_73] at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_73] at org.springframework.data.repository.core.support.ImplementationInvocationMetadata.invoke(ImplementationInvocationMetadata.java:72) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:382) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:205) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:550) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:155) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:130) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) ~[spring-data-commons-2.3.9.RELEASE.jar:2.3.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367) ~[spring-tx-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118) ~[spring-tx-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.22.RELEASE.jar:5.2.22.RELEASE] at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.2.22.RELEASE.jar:5.2.22.RELEASE] ... 109 more
代碼分析
從以上兩種模式下的異常棧分析代碼路徑：
org.springframework.data.jpa.repository.support.SimpleJpaRepository.saveAndFlush
org.springframework.data.jpa.repository.support.SimpleJpaRepository.flush
org.hibernate.internal.SessionImpl.flush
org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener
org.hibernate.event.internal.DefaultFlushEventListener.onFlush
org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions
org.hibernate.engine.spi.ActionQueue.executeActions
ActionQueue.executeActions邏輯如下：
hibernate-core-5.4.32.Final-sources.jar!/org/hibernate/engine/spi/ActionQueue.java
/**
* Perform all currently queued actions.
*
* @throws HibernateException error executing queued actions.
*/
public void executeActions() throws HibernateException {
if ( hasUnresolvedEntityInsertActions() ) {
throw new IllegalStateException( "About to execute actions, but there are unresolved entity insert actions." );
}
for ( ListProvider listProvider : EXECUTABLE_LISTS_MAP.values() ) {
ExecutableList<?> l = listProvider.get( this );
if ( l != null && !l.isEmpty() ) {
executeActions( l );
}
}
}
/**
* Perform {@link org.hibernate.action.spi.Executable#execute()} on each element of the list
*
* @param list The list of Executable elements to be performed
*
* @throws HibernateException
*/
private <E extends Executable & Comparable<?> & Serializable> void executeActions(ExecutableList<E> list) throws HibernateException {
// todo : consider ways to improve the double iteration of Executables here:
// 1) we explicitly iterate list here to perform Executable#execute()
// 2) ExecutableList#getQuerySpaces also iterates the Executables to collect query spaces.
try {
for ( E e : list ) {
try {
e.execute();
}
finally {
if( e.getBeforeTransactionCompletionProcess() != null ) {
if( beforeTransactionProcesses == null ) {
beforeTransactionProcesses = new BeforeTransactionCompletionProcessQueue( session );
}
beforeTransactionProcesses.register(e.getBeforeTransactionCompletionProcess());
}
if( e.getAfterTransactionCompletionProcess() != null ) {
if( afterTransactionProcesses == null ) {
afterTransactionProcesses = new AfterTransactionCompletionProcessQueue( session );
}
afterTransactionProcesses.register(e.getAfterTransactionCompletionProcess());
}
}
}
}
finally {
if ( session.getFactory().getSessionFactoryOptions().isQueryCacheEnabled() ) {
// Strictly speaking, only a subset of the list may have been processed if a RuntimeException occurs.
// We still invalidate all spaces. I don't see this as a big deal - after all, RuntimeExceptions are
// unexpected.
Set<Serializable> propertySpaces = list.getQuerySpaces();
invalidateSpaces( propertySpaces.toArray( new Serializable[propertySpaces.size()] ) );
}
}
list.clear();
session.getJdbcCoordinator().executeBatch();
}
這里在for循環(huán)里頭調(diào)用了e.execute()，同時(shí)在循環(huán)之后，finally之后調(diào)用了session.getJdbcCoordinator().executeBatch()
其中，EXECUTABLE_LISTS_MAP中的Executable包括：EntityInsertAction、EntityUpdateAction、EntityDeleteAction等。
Executable.execute邏輯如下：
hibernate-core-5.4.32.Final-sources.jar!/org/hibernate/action/internal/EntityUpdateAction.java
@Override
public void execute() throws HibernateException {
final Serializable id = getId();
final EntityPersister persister = getPersister();
final SharedSessionContractImplementor session = getSession();
final Object instance = getInstance();
final boolean veto = preUpdate();
final SessionFactoryImplementor factory = session.getFactory();
Object previousVersion = this.previousVersion;
if ( persister.isVersionPropertyGenerated() ) {
// we need to grab the version value from the entity, otherwise
// we have issues with generated-version entities that may have
// multiple actions queued during the same flush
previousVersion = persister.getVersion( instance );
}
final Object ck;
if ( persister.canWriteToCache() ) {
final EntityDataAccess cache = persister.getCacheAccessStrategy();
ck = cache.generateCacheKey(
id,
persister,
factory,
session.getTenantIdentifier()
);
lock = cache.lockItem( session, ck, previousVersion );
}
else {
ck = null;
}
if ( !veto ) {
persister.update(
id,
state,
dirtyFields,
hasDirtyCollection,
previousState,
previousVersion,
instance,
rowId,
session
);
}
final EntityEntry entry = session.getPersistenceContextInternal().getEntry( instance );
if ( entry == null ) {
throw new AssertionFailure( "possible nonthreadsafe access to session" );
}
if ( entry.getStatus()==Status.MANAGED || persister.isVersionPropertyGenerated() ) {
// get the updated snapshot of the entity state by cloning current state;
// it is safe to copy in place, since by this time no-one else (should have)
// has a reference to the array
TypeHelper.deepCopy(
state,
persister.getPropertyTypes(),
persister.getPropertyCheckability(),
state,
session
);
if ( persister.hasUpdateGeneratedProperties() ) {
// this entity defines property generation, so process those generated
// values...
persister.processUpdateGeneratedProperties( id, instance, state, session );
if ( persister.isVersionPropertyGenerated() ) {
nextVersion = Versioning.getVersion( state, persister );
}
}
// have the entity entry doAfterTransactionCompletion post-update processing, passing it the
// update state and the new version (if one).
entry.postUpdate( instance, state, nextVersion );
}
final StatisticsImplementor statistics = factory.getStatistics();
if ( persister.canWriteToCache() ) {
if ( persister.isCacheInvalidationRequired() || entry.getStatus()!= Status.MANAGED ) {
persister.getCacheAccessStrategy().remove( session, ck);
}
else if ( session.getCacheMode().isPutEnabled() ) {
//TODO: inefficient if that cache is just going to ignore the updated state!
final CacheEntry ce = persister.buildCacheEntry( instance,state, nextVersion, getSession() );
cacheEntry = persister.getCacheEntryStructure().structure( ce );
final boolean put = cacheUpdate( persister, previousVersion, ck );
if ( put && statistics.isStatisticsEnabled() ) {
statistics.entityCachePut(
StatsHelper.INSTANCE.getRootEntityRole( persister ),
getPersister().getCacheAccessStrategy().getRegion().getName()
);
}
}
}
session.getPersistenceContextInternal().getNaturalIdHelper().manageSharedNaturalIdCrossReference(
persister,
id,
state,
previousNaturalIdValues,
CachedNaturalIdValueSource.UPDATE
);
postUpdate();
if ( statistics.isStatisticsEnabled() && !veto ) {
statistics.updateEntity( getPersister().getEntityName() );
}
}
調(diào)用了persister的update方法。
AbstractEntityPersister.update
hibernate-core-5.4.32.Final-sources.jar!/org/hibernate/persister/entity/AbstractEntityPersister.java
public boolean update(
final Serializable id,
final Object[] fields,
final Object[] oldFields,
final Object rowId,
final boolean[] includeProperty,
final int j,
final Object oldVersion,
final Object object,
final String sql,
final SharedSessionContractImplementor session) throws HibernateException {
final Expectation expectation = Expectations.appropriateExpectation( updateResultCheckStyles[j] );
final int jdbcBatchSizeToUse = session.getConfiguredJdbcBatchSize();
// IMPLEMENTATION NOTE: If Session#saveOrUpdate or #update is used to update an entity, then
// Hibernate does not have a database snapshot of the existing entity.
// As a result, oldFields will be null.
// Don't use a batch if oldFields == null and the jth table is optional (isNullableTable( j ),
// because there is no way to know that there is actually a row to update. If the update
// was batched in this case, the batch update would fail and there is no way to fallback to
// an insert.
final boolean useBatch =
expectation.canBeBatched() &&
isBatchable() &&
jdbcBatchSizeToUse > 1 &&
( oldFields != null || !isNullableTable( j ) );
if ( useBatch && updateBatchKey == null ) {
updateBatchKey = new BasicBatchKey(
getEntityName() + "#UPDATE",
expectation
);
}
final boolean callable = isUpdateCallable( j );
final boolean useVersion = j == 0 && isVersioned();
if ( LOG.isTraceEnabled() ) {
LOG.tracev( "Updating entity: {0}", MessageHelper.infoString( this, id, getFactory() ) );
if ( useVersion ) {
LOG.tracev( "Existing version: {0} -> New version:{1}", oldVersion, fields[getVersionProperty()] );
}
}
try {
int index = 1; // starting index
final PreparedStatement update;
if ( useBatch ) {
update = session
.getJdbcCoordinator()
.getBatch( updateBatchKey )
.getBatchStatement( sql, callable );
}
else {
update = session
.getJdbcCoordinator()
.getStatementPreparer()
.prepareStatement( sql, callable );
}
try {
index += expectation.prepare( update );
//Now write the values of fields onto the prepared statement
index = dehydrate(
id,
fields,
rowId,
includeProperty,
propertyColumnUpdateable,
j,
update,
session,
index,
true
);
// Write any appropriate versioning conditional parameters
if ( useVersion && entityMetamodel.getOptimisticLockStyle().isVersion()) {
if ( checkVersion( includeProperty ) ) {
getVersionType().nullSafeSet( update, oldVersion, index, session );
}
}
else if ( isAllOrDirtyOptLocking() && oldFields != null ) {
boolean[] versionability = getPropertyVersionability(); //TODO: is this really necessary????
boolean[] includeOldField = entityMetamodel.getOptimisticLockStyle().isAll()
? getPropertyUpdateability()
: includeProperty;
Type[] types = getPropertyTypes();
for ( int i = 0; i < entityMetamodel.getPropertySpan(); i++ ) {
boolean include = includeOldField[i] &&
isPropertyOfTable( i, j ) &&
versionability[i]; //TODO: is this really necessary????
if ( include ) {
boolean[] settable = types[i].toColumnNullness( oldFields[i], getFactory() );
types[i].nullSafeSet(
update,
oldFields[i],
index,
settable,
session
);
index += ArrayHelper.countTrue( settable );
}
}
}
if ( useBatch ) {
session.getJdbcCoordinator().getBatch( updateBatchKey ).addToBatch();
return true;
}
else {
return check(
session.getJdbcCoordinator().getResultSetReturn().executeUpdate( update ),
id,
j,
expectation,
update,
sql
);
}
}
catch (SQLException e) {
if ( useBatch ) {
session.getJdbcCoordinator().abortBatch();
}
throw e;
}
finally {
if ( !useBatch ) {
session.getJdbcCoordinator().getResourceRegistry().release( update );
session.getJdbcCoordinator().afterStatementExecution();
}
}
}
catch (SQLException e) {
throw getFactory().getSQLExceptionHelper().convert(
e,
"could not update: " + MessageHelper.infoString( this, id, getFactory() ),
sql
);
}
}
關(guān)鍵之處：
useBatch的賦值邏輯
public boolean isBatchable() {
return optimisticLockStyle().isNone()
|| !isVersioned() && optimisticLockStyle().isVersion()
|| getFactory().getSessionFactoryOptions().isJdbcBatchVersionedData();
}
1. 配置了`spring.jpa.properties.hibernate.jdbc.batch_versioned_data`為true；
2. jdbcBatchSizeToUse > 1, 即`spring.jpa.properties.hibernate.jdbc.batch_size`大于0
- 如果useBatch為true
調(diào)用session.getJdbcCoordinator().getBatch(updateBatchKey).addToBatch();
這里的updateBatchKey為com.example.domain.User#UPDATE；此處僅是將PreparedStatement放入待執(zhí)行隊(duì)列。
之后便執(zhí)行session.getJdbcCoordinator().executeBatch()邏輯；請(qǐng)看BatchingBatch.performExecution
- 如果useBatch為false
調(diào)用session.getJdbcCoordinator().getResultSetReturn().executeUpdate( update )，并調(diào)用check方法執(zhí)行檢查。此處檢查失敗，則會(huì)拋出樂(lè)觀鎖異常！
BatchingBatch.performExecution
hibernate-core-5.4.32.Final-sources.jar!/org/hibernate/engine/jdbc/batch/internal/BatchingBatch.java
private void performExecution() {
LOG.debugf( "Executing batch size: %s", batchPosition );
try {
for ( Map.Entry<String,PreparedStatement> entry : getStatements().entrySet() ) {
try {
final PreparedStatement statement = entry.getValue();
final int[] rowCounts;
try {
getJdbcCoordinator().getJdbcSessionOwner().getJdbcSessionContext().getObserver().jdbcExecuteBatchStart();
rowCounts = statement.executeBatch();
}
finally {
getJdbcCoordinator().getJdbcSessionOwner().getJdbcSessionContext().getObserver().jdbcExecuteBatchEnd();
}
checkRowCounts( rowCounts, statement );
}
catch ( SQLException e ) {
abortBatch();
throw sqlExceptionHelper().convert( e, "could not execute batch", entry.getKey() );
}
}
}
catch ( RuntimeException re ) {
LOG.unableToExecuteBatch( re.getMessage() );
throw re;
}
finally {
batchPosition = 0;
}
}
可以看到這里調(diào)用了statement.executeBatch()，并返回了int[] rowCounts;然后調(diào)用checkRowCounts( rowCounts, statement ); >Expectations#BasicExpectation.checkBatched 此處檢查失敗，則會(huì)拋出樂(lè)觀鎖異常！
問(wèn)題原因
非批量模式下，檢查執(zhí)行結(jié)果是調(diào)用的checkNonBatched方法，該方法僅檢查更新條目數(shù)是否一致：
private void checkNonBatched(int rowCount, String statementSQL) {
if ( expectedRowCount > rowCount ) {
throw new StaleStateException(
"Unexpected row count: " + rowCount + "; expected: " + expectedRowCount
+ "; statement executed: " + statementSQL
);
}
if ( expectedRowCount < rowCount ) {
String msg = "Unexpected row count: " + rowCount + "; expected: " + expectedRowCount;
throw new TooManyRowsAffectedException( msg, expectedRowCount, rowCount );
}
}
批量模式下，檢查執(zhí)行結(jié)果是調(diào)用的checkBatched方法，檢查邏輯如下：
private void checkBatched(int rowCount, int batchPosition, String statementSQL) {
if ( rowCount == -2 ) {
LOG.debugf( "Success of batch update unknown: %s", batchPosition );
}
else if ( rowCount == -3 ) {
throw new BatchFailedException( "Batch update failed: " + batchPosition );
}
else {
if ( expectedRowCount > rowCount ) {
throw new StaleStateException(
"Batch update returned unexpected row count from update ["
+ batchPosition + "]; actual row count: " + rowCount
+ "; expected: " + expectedRowCount + "; statement executed: "
+ statementSQL
);
}
if ( expectedRowCount < rowCount ) {
String msg = "Batch update returned unexpected row count from update [" +
batchPosition + "]; actual row count: " + rowCount +
"; expected: " + expectedRowCount;
throw new BatchedTooManyRowsAffectedException( msg, expectedRowCount, rowCount, batchPosition );
}
}
}
問(wèn)題便在于此！
int[] executeBatch() throws SQLException
返回值說(shuō)明：
① 大于或等于零的數(shù)字，表示命令已成功處理，并且是更新計(jì)數(shù)，給出了數(shù)據(jù)庫(kù)中受命令影響的行數(shù)執(zhí)行；
② SUCCESS_NO_INFO ( -2)的值，表示命令處理成功，但受影響的行數(shù)未知；
③ 如果批量更新中的命令之一無(wú)法正確執(zhí)行，此方法引發(fā)BatchUpdateException，JDBC Driver可能會(huì)也可能不會(huì)繼續(xù)處理剩余的命令。但是Driver的行為是與特定的DBMS綁定的，要么總是繼續(xù)處理命令，要么從不繼續(xù)處理命令。如果驅(qū)動(dòng)程序繼續(xù)處理，方法將返回EXECUTE_FAILED(-3)。
在實(shí)際的測(cè)試過(guò)程中發(fā)現(xiàn)：
| DB類型 | 是否可以返回實(shí)際影響行數(shù) | 備注 |
|---|---|---|
| MySQL | 是 | |
| Oracle | 否 | 每個(gè)數(shù)組位置值均為-2 |
在Oracle的驅(qū)動(dòng)中沒(méi)有實(shí)現(xiàn)該功能，即提交成功后不能返回影響行數(shù)，所以返回-2。
Oracle驅(qū)動(dòng)源碼如下：oracle.jdbc.driver.OraclePreparedStatement#executeBatch
public int[] executeBatch() throws SQLException {
synchronized (this.connection) {
int[] arrayOfInt = new int[this.currentRank];
/* 此處省略N行代碼 */
if ((this.sqlKind != 1) && (this.sqlKind != 4)) {
for (i = 0; i < arrayOfInt.length; i++) {
arrayOfInt[i] = -2; // 關(guān)鍵看這行
}
}
this.connection.registerHeartbeat();
return arrayOfInt;
}
}
根據(jù)StackOverflow上的說(shuō)法，Oracle 11g之前的版本，executeBatch方法返回的均是-2，eg.
解決方案
Hibernate對(duì)于這個(gè)問(wèn)題有自己的處理辦法，就是設(shè)置一個(gè)jdbc和數(shù)據(jù)庫(kù)的連接屬性hibernate.jdbc.use_scrollable_resultset =true。
如果你想讓你的JDBC驅(qū)動(dòng)從executeBatch()返回正確的行計(jì)數(shù) , 那么將此屬性設(shè)為true(開(kāi)啟這個(gè)選項(xiàng)通常是安全的). 同時(shí)，Hibernate將為自動(dòng)版本化的數(shù)據(jù)使用批量DML. 默認(rèn)值為false. eg. true | false
以上就是Spring Data JPA開(kāi)啟批量更新時(shí)樂(lè)觀鎖失效問(wèn)題的解決方法的詳細(xì)內(nèi)容，更多關(guān)于Spring Data JPA樂(lè)觀鎖失效的資料請(qǐng)關(guān)注腳本之家其它相關(guān)文章！
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