Redis事务异常：Caused by: io.lettuce.core.RedisCommandExecutionException: ERR EXEC without MULTI
2020-07-29 21:15:00.635 INFO 26920 --- [ main] io.lettuce.core.EpollProvider : Starting without optional epoll library 2020-07-29 21:15:00.643 INFO 26920 --- [ main] io.lettuce.core.KqueueProvider : Starting without optional kqueue library org.springframework.data.redis.RedisSystemException: Error in execution; nested exception is io.lettuce.core.RedisCommandExecutionException: ERR EXEC without MULTI at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:54) at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:52) at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:41) at org.springframework.data.redis.PassThroughExceptionTranslationStrategy.translate(PassThroughExceptionTranslationStrategy.java:44) at org.springframework.data.redis.FallbackExceptionTranslationStrategy.translate(FallbackExceptionTranslationStrategy.java:42) at org.springframework.data.redis.connection.lettuce.LettuceConnection.convertLettuceAccessException(LettuceConnection.java:268) at org.springframework.data.redis.connection.lettuce.LettuceConnection.exec(LettuceConnection.java:653) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:483) at org.springframework.data.redis.core.CloseSuppressingInvocationHandler.invoke(CloseSuppressingInvocationHandler.java:61) at com.sun.proxy.$Proxy83.exec(Unknown Source) at org.springframework.data.redis.core.RedisTemplate$$Lambda$515/1273684451.doInRedis(Unknown Source) at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:224) at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:184) at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:171) at org.springframework.data.redis.core.RedisTemplate.execRaw(RedisTemplate.java:696) at org.springframework.data.redis.core.RedisTemplate.exec(RedisTemplate.java:677) at com.xds.redis.manager.XdsRedisManagerApplicationTests.redisTransaction(XdsRedisManagerApplicationTests.java:60) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:483) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74) at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84) at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68) at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47) at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242) at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70) Caused by: io.lettuce.core.RedisCommandExecutionException: ERR EXEC without MULTI at io.lettuce.core.ExceptionFactory.createExecutionException(ExceptionFactory.java:135) at io.lettuce.core.ExceptionFactory.createExecutionException(ExceptionFactory.java:108) at io.lettuce.core.protocol.AsyncCommand.completeResult(AsyncCommand.java:120) at io.lettuce.core.protocol.AsyncCommand.complete(AsyncCommand.java:111) at io.lettuce.core.protocol.CommandHandler.complete(CommandHandler.java:646) at io.lettuce.core.protocol.CommandHandler.decode(CommandHandler.java:604) at io.lettuce.core.protocol.CommandHandler.channelRead(CommandHandler.java:556) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1408) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:930) at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:677) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:612) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:529) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:491) at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:905) at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) at java.lang.Thread.run(Thread.java:745)
出现场景：使用RedisTemplate操作redis事务，如
redisTemplate.multi(); redisTemplate.opsForValue().set("username", "xds"); List<Object> exec = redisTemplate.exec(); System.out.println(JSONObject.toJSONString(exec));
上面报错的意思是我们在执行exec()方法之前没有先执行mutli()方法，所以抛了异常，解决办法是在代码前将enableTransactionSupport设置为true，如下
redisTemplate.setEnableTransactionSupport(true); redisTemplate.multi(); redisTemplate.opsForValue().set("username", "xds"); List<Object> exec = redisTemplate.exec(); System.out.println(JSONObject.toJSONString(exec));
在执行redisTemplate.multi()、redisTemplate.opsForValue.set("username","xds)、redisTemplate.exec()方法时，最终会调用RedisTemplate.execute(org.springframework.data.redis.core.RedisCallback<T>, boolean, boolean)方法，如下
@Nullable public <T> T execute(RedisCallback<T> action, boolean exposeConnection, boolean pipeline) { Assert.isTrue(this.initialized, "template not initialized; call afterPropertiesSet() before using it"); Assert.notNull(action, "Callback object must not be null"); RedisConnectionFactory factory = this.getRequiredConnectionFactory(); RedisConnection conn = null; Object var11; try { //enableTransactionSupport标识是否开启事务支持，默认为false if (this.enableTransactionSupport) { //enableTransactionSupport为true，为当前连接池开启事务，将当前RedisConnectionFactory放入事务管理器 //从事务管理器中获取RedisConnection对象，保证接下来的每一个操作使用的都是同一个RedisConnection对象 conn = RedisConnectionUtils.bindConnection(factory, this.enableTransactionSupport); } else { //enableTransactionSupport为false，当前连接池未开启事务，每次操作都是连接池中重新获取的没有无事务的RRedisConnection对象 //所以在执行List<Object> exec = redisTemplate.exec();时候就会抛出上面的异常 conn = RedisConnectionUtils.getConnection(factory); } boolean existingConnection = TransactionSynchronizationManager.hasResource(factory); RedisConnection connToUse = this.preProcessConnection(conn, existingConnection); boolean pipelineStatus = connToUse.isPipelined(); if (pipeline && !pipelineStatus) { connToUse.openPipeline(); } RedisConnection connToExpose = exposeConnection ? connToUse : this.createRedisConnectionProxy(connToUse); T result = action.doInRedis(connToExpose); if (pipeline && !pipelineStatus) { connToUse.closePipeline(); } var11 = this.postProcessResult(result, connToUse, existingConnection); } finally { RedisConnectionUtils.releaseConnection(conn, factory); } return var11; }
对于RedisConnection对象的获取，上面源码中根据是否开启事务支持分了两个方法去获取，但最终这两个方法都会调用到同一个方法去执行，唯一不同的是传递的参数值不一样
/** * 1.enableTransactionSupport=true;bind=true; * 2.enableTransactionSupport=false;bind=false; */ public static RedisConnection doGetConnection(RedisConnectionFactory factory, boolean allowCreate, boolean bind, boolean enableTransactionSupport) { Assert.notNull(factory, "No RedisConnectionFactory specified"); //从事务管理器TransactionSynchronizationManager获取连接池对象RedisConnectionHolder RedisConnectionUtils.RedisConnectionHolder connHolder = (RedisConnectionUtils.RedisConnectionHolder)TransactionSynchronizationManager.getResource(factory); if (connHolder != null) { if (enableTransactionSupport) { potentiallyRegisterTransactionSynchronisation(connHolder, factory); } //返回事务管理器中的RedisConnection对象 return connHolder.getConnection(); } else if (!allowCreate) { throw new IllegalArgumentException("No connection found and allowCreate = false"); } else { if (log.isDebugEnabled()) { log.debug("Opening RedisConnection"); } //获取使用当前连接池中RedisConnection对象 RedisConnection conn = factory.getConnection(); if (bind) { //如果bind为ture，新建一个RedisConnection对象 RedisConnection connectionToBind = conn; if (enableTransactionSupport && isActualNonReadonlyTransactionActive()) { connectionToBind = createConnectionProxy(conn, factory); } //新建RedisConnectionHolder对象 connHolder = new RedisConnectionUtils.RedisConnectionHolder(connectionToBind); //将RedisConnectionHolder对象放入事务管理器中 TransactionSynchronizationManager.bindResource(factory, connHolder); if (enableTransactionSupport) { potentiallyRegisterTransactionSynchronisation(connHolder, factory); } return connHolder.getConnection(); } else { //bind为false，返回重新从连接池中获取的RedisConnection return conn; } } }
如果是开启了事务支持，redisTemplate.multi()执行后调用doGetConnection(...)方法，会首次将RedisConnection对象加入到事务管理器中，后面的方法每次调用doGetConnection(...)方法，都会基于事务管理器中的RedisConnection对象进行操作。
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