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[英]Lock wait timeout exceeded with Hibernate and MySQL (using play framework)
[英]hibernate Lock wait timeout exceeded;
我正在使用Hibernate,試圖模擬2個並發更新到數據庫中的同一行。
編輯:我移動em1.getTransaction()。提交在em1.flush()之后; 我沒有得到任何StaleObjectException,這兩個事務成功提交。
Session em1=Manager.sessionFactory.openSession();
Session em2=Manager.sessionFactory.openSession();
em1.getTransaction().begin();
em2.getTransaction().begin();
UserAccount c1 = (UserAccount)em1.get( UserAccount.class, "root" );
UserAccount c2 = (UserAccount)em2.get( UserAccount.class, "root" );
c1.setBalance( c1.getBalance() -1 );
em1.flush();
System.out.println("balance1 is "+c2.getBalance());
c2.setBalance( c2.getBalance() -1 );
em2.flush(); // fail
em1.getTransaction().commit();
em2.getTransaction().commit();
System.out.println("balance2 is "+c2.getBalance());
我在em2.flush()
上得到以下異常。 為什么?
2009-12-23 21:48:37,648 WARN JDBCExceptionReporter:100 - SQL Error: 1205, SQLState: 41000
2009-12-23 21:48:37,649 ERROR JDBCExceptionReporter:101 - Lock wait timeout exceeded; try restarting transaction
2009-12-23 21:48:37,650 ERROR AbstractFlushingEventListener:324 - Could not synchronize database state with session
org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch update
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275)
at org.hibernate.persister.entity.AbstractEntityPersister.processGeneratedProperties(AbstractEntityPersister.java:3702)
at org.hibernate.persister.entity.AbstractEntityPersister.processUpdateGeneratedProperties(AbstractEntityPersister.java:3691)
at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:147)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:168)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1028)
at com.ch.whoisserver.test.StressTest.main(StressTest.java:54)
Caused by: java.sql.BatchUpdateException: Lock wait timeout exceeded; try restarting transaction
at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:1213)
at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:912)
at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
... 10 more
好吧,你正試圖陷入僵局並且你取得了成功:-)
真實生活模擬將在第一個和第二個實體管理器以及單獨線程中的適當更新/事務。 那樣你就有:
請注意,在那時(上面的#4),您將覆蓋Transaction1所做的更改。 Hibernate可以使用樂觀鎖定和悲觀鎖定來防止這種情況發生。
更新 (根據評論):
如果實體是版本化的,則Transaction2(上面的#4)將失敗。 但是,您發布的代碼沒有到達那一點,因為Transaction2無法獲得鎖定,如上所述。 如果您想要專門測試樂觀版本控件是否正常工作,您可以執行以下操作:
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