java - Getting "Deadlock found when trying to get lock; try restarting transaction"

Question

My Application(java spring-core) has several threads running concurrently and accessing db, I am getting exception in some peaktime

07:43:33,400 WARN  [org.hibernate.util.JDBCExceptionReporter] SQL Error: 1213, SQLState: 40001
07:43:33,808 ERROR [org.hibernate.util.JDBCExceptionReporter] Deadlock found when trying to get lock; try restarting transaction
07:43:33,808 ERROR [org.hibernate.event.def.AbstractFlushingEventListener] Could not synchronize database state with session
org.hibernate.exception.LockAcquisitionException: could not insert: [com.xminds.bestfriend.frontend.model.Question]
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:107)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2436)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2856)
    at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:79)
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:265)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:184)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133)
    at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:656)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:754)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:723)
    at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:147)
    at com.xminds.bestfriend.consumers.Base.onMessage(Base.java:96)
    at org.springframework.jms.listener.adapter.MessageListenerAdapter.onMessage(MessageListenerAdapter.java:339)
    at org.springframework.jms.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:535)
    at org.springframework.jms.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:495)
    at org.springframework.jms.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:467)
    at org.springframework.jms.listener.AbstractPollingMessageListenerContainer.doReceiveAndExecute(AbstractPollingMessageListenerContainer.java:325)
    at org.springframework.jms.listener.AbstractPollingMessageListenerContainer.receiveAndExecute(AbstractPollingMessageListenerContainer.java:263)
    at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener(DefaultMessageListenerContainer.java:1058)
    at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.executeOngoingLoop(DefaultMessageListenerContainer.java:1050)
    at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.run(DefaultMessageListenerContainer.java:947)
    at java.lang.Thread.run(Thread.java:662)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.Util.getInstance(Util.java:386)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1065)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4074)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4006)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2468)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2629)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2719)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2450)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2371)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2355)
    at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:105)
    at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:46)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2416)
    ... 25 more

My code looks

try
{
       this.consumerTransactionTemplate.execute(new TransactionCallbackWithoutResult(){

                    @Override
                    protected void doInTransactionWithoutResult(
                            TransactionStatus status)
                    {
                        process();
                    }

                });

  }
  catch(Exception e){
     logger.error("Exception occured " , e);
      //TODO: Exception handling
  }

Answer 1

MySQL's InnoDB engine sports row-level locking, which can lead to deadlocks even when your code is inserting or updating a single row (specially if there are several indexes on the table being updated). Your best bet is to design the code around this in order to retry a transaction if it fails due to a deadlock. Some useful info about MySQL deadlock diagnose and possible workarounds is available here.

An interesting implementation of deadlock retry via AOP in Spring is available here. This way you just need to add the annotation to the method you want to retry in case of deadlock.