sql-server - SQL Server `sp_who2` 过程显示 sleep 连接的长锁

标签 sql-server azure entity-framework-6 database-connection sp-who2

我正在运行 Azure SQL Server，并且使用它的 WebApi 应用程序存在一些问题。在重负载下的某个时刻，应用程序开始创建大量连接，并且 sp_who2 显示我有几个长锁。跟踪锁链后，我可以看到罪魁祸首是一个 sleep 连接，它目前不执行任何操作(status = 'sleeping' 且 BlkBy = '.')。

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当我对 WebApi 进程进行内存转储时，我可以看到大多数进程都有以下调用堆栈:

[Managed to Native Transition]  
    >   mscorlib.dll!System.Threading.SemaphoreSlim.WaitUntilCountOrTimeout(int millisecondsTimeout, uint startTime, System.Threading.CancellationToken cancellationToken)  Unknown
        mscorlib.dll!System.Threading.SemaphoreSlim.Wait(int millisecondsTimeout, System.Threading.CancellationToken cancellationToken) Unknown
        mscorlib.dll!System.Threading.SemaphoreSlim.Wait()  Unknown
        System.Data.dll!System.Data.SqlClient.SqlInternalConnectionTds.SyncAsyncLock.Wait(bool canReleaseFromAnyThread) Unknown
        System.Data.dll!System.Data.SqlClient.SqlInternalConnectionTds.ObtainAdditionalLocksForClose()  Unknown
        System.Data.dll!System.Data.ProviderBase.DbConnectionInternal.CloseConnection(System.Data.Common.DbConnection owningObject, System.Data.ProviderBase.DbConnectionFactory connectionFactory) Unknown
        System.Data.dll!System.Data.SqlClient.SqlConnection.Close() Unknown
        EntityFramework.dll!System.Data.Entity.Infrastructure.Interception.InternalDispatcher<System.Data.Entity.Infrastructure.Interception.IDbConnectionInterceptor>.Dispatch<System.Data.Common.DbConnection, System.Data.Entity.Infrastructure.Interception.DbConnectionInterceptionContext>(System.Data.Common.DbConnection target, System.Action<System.Data.Common.DbConnection, System.Data.Entity.Infrastructure.Interception.DbConnectionInterceptionContext> operation, System.Data.Entity.Infrastructure.Interception.DbConnectionInterceptionContext interceptionContext, System.Action<System.Data.Entity.Infrastructure.Interception.IDbConnectionInterceptor, System.Data.Common.DbConnection, System.Data.Entity.Infrastructure.Interception.DbConnectionInterceptionContext> executing, System.Action<System.Data.Entity.Infrastructure.Interception.IDbConnectionInterceptor, System.Data.Common.DbConnection, System.Data.Entity.Infrastructure.Interception.DbConnectionInterceptionContext> executed) Unknown
        EntityFramework.dll!System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Close(System.Data.Common.DbConnection connection, System.Data.Entity.Infrastructure.Interception.DbInterceptionContext interceptionContext)   Unknown
        EntityFramework.dll!System.Data.Entity.Core.EntityClient.EntityConnection.StoreCloseHelper()    Unknown
        EntityFramework.dll!System.Data.Entity.Core.Objects.ObjectContext.ReleaseConnection()   Unknown
        EntityFramework.dll!System.Data.Entity.Core.Common.Internal.Materialization.Shaper<My.EF6.Entity>.Finally() Unknown
        EntityFramework.dll!System.Data.Entity.Core.Common.Internal.Materialization.Shaper<System.__Canon>.ObjectQueryNestedEnumerator.Dispose()    Unknown
        EntityFramework.dll!System.Data.Entity.Internal.LazyAsyncEnumerator<System.__Canon>.Dispose()   Unknown
        EntityFramework.dll!System.Data.Entity.Infrastructure.IDbAsyncEnumerableExtensions.FirstOrDefaultAsync<My.EF6.Entity>(System.Data.Entity.Infrastructure.IDbAsyncEnumerable<My.EF6.Entity> source, System.Threading.CancellationToken cancellationToken) Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()    Unknown
        EntityFramework.dll!System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter<bool>.UnsafeOnCompleted.AnonymousMethod__0() Unknown
        mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task<bool>.TrySetResult(bool result)    Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<bool>.SetResult(bool result)    Unknown
        EntityFramework.dll!System.Data.Entity.Internal.LazyAsyncEnumerator<My.EF6.Entity>.FirstMoveNextAsync(System.Threading.CancellationToken cancellationToken) Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()    Unknown
        EntityFramework.dll!System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter<System.__Canon>.UnsafeOnCompleted.AnonymousMethod__0()   Unknown
        mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)    Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity>>.SetResult(System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity> result)  Unknown
        EntityFramework.dll!System.Data.Entity.Core.Objects.ObjectQuery<My.EF6.Entity>.GetResultsAsync(System.Data.Entity.Core.Objects.MergeOption? forMergeOption, System.Data.Entity.Infrastructure.IDbExecutionStrategy executionStrategy, System.Threading.CancellationToken cancellationToken) Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()    Unknown
        EntityFramework.dll!System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter<System.__Canon>.UnsafeOnCompleted.AnonymousMethod__0()   Unknown
        mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)    Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity>>.SetResult(System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity> result)  Unknown
        EntityFramework.SqlServer.dll!System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.ExecuteAsyncImplementation<System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity>>(System.Func<System.Threading.Tasks.Task<System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity>>> func)  Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()    Unknown
        mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)    Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity>>.SetResult(System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity> result)  Unknown
        EntityFramework.dll!System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransactionAsync<System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity>>(System.Func<System.Threading.Tasks.Task<System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity>>> func, System.Data.Entity.Infrastructure.IDbExecutionStrategy executionStrategy, bool startLocalTransaction, bool releaseConnectionOnSuccess, System.Threading.CancellationToken cancellationToken)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()    Unknown
        EntityFramework.dll!System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter<System.__Canon>.UnsafeOnCompleted.AnonymousMethod__0()   Unknown
        mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)    Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity>>.SetResult(System.Data.Entity.Core.Objects.ObjectResult<My.EF6.Entity> result)  Unknown
        EntityFramework.dll!System.Data.Entity.Core.Objects.Internal.ObjectQueryExecutionPlan.ExecuteAsync<My.EF6.Entity>(System.Data.Entity.Core.Objects.ObjectContext context, System.Data.Entity.Core.Objects.ObjectParameterCollection parameterValues, System.Threading.CancellationToken cancellationToken)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()    Unknown
        EntityFramework.dll!System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter<System.__Canon>.UnsafeOnCompleted.AnonymousMethod__0()   Unknown
        mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)    Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Data.Common.DbDataReader>.SetResult(System.Data.Common.DbDataReader result)  Unknown
        EntityFramework.dll!System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition.ExecuteStoreCommandsAsync(System.Data.Entity.Core.EntityClient.EntityCommand entityCommand, System.Data.CommandBehavior behavior, System.Threading.CancellationToken cancellationToken)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
        mscorlib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.MoveNextRunner.Run()    Unknown
        EntityFramework.dll!System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter<System.__Canon>.UnsafeOnCompleted.AnonymousMethod__0()   Unknown
        mscorlib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining, ref System.Threading.Tasks.Task currentTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task.Finish(bool bUserDelegateExecuted) Unknown
        mscorlib.dll!System.Threading.Tasks.Task.ExecuteWithThreadLocal(ref System.Threading.Tasks.Task currentTaskSlot)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.ExecuteEntry(bool bPreventDoubleExecution) Unknown
        mscorlib.dll!System.Threading.Tasks.ThreadPoolTaskScheduler.TryExecuteTaskInline(System.Threading.Tasks.Task task, bool taskWasPreviouslyQueued)    Unknown
        mscorlib.dll!System.Threading.Tasks.TaskScheduler.TryRunInline(System.Threading.Tasks.Task task, bool taskWasPreviouslyQueued)  Unknown
        mscorlib.dll!System.Threading.Tasks.TaskContinuation.InlineIfPossibleOrElseQueue(System.Threading.Tasks.Task task, bool needsProtection)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task<System.__Canon>.TrySetResult(System.__Canon result)    Unknown
        mscorlib.dll!System.Threading.Tasks.UnwrapPromise<System.Data.SqlClient.SqlDataReader>.TrySetFromTask(System.Threading.Tasks.Task task, bool lookForOce)    Unknown
        mscorlib.dll!System.Threading.Tasks.UnwrapPromise<System.__Canon>.ProcessInnerTask(System.Threading.Tasks.Task task)    Unknown
        mscorlib.dll!System.Threading.Tasks.UnwrapPromise<System.__Canon>.Invoke(System.Threading.Tasks.Task completingTask)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.FinishContinuations()  Unknown
        mscorlib.dll!System.Threading.Tasks.Task.Finish(bool bUserDelegateExecuted) Unknown
        mscorlib.dll!System.Threading.Tasks.Task.ExecuteWithThreadLocal(ref System.Threading.Tasks.Task currentTaskSlot)    Unknown
        mscorlib.dll!System.Threading.Tasks.Task.ExecuteEntry(bool bPreventDoubleExecution) Unknown
        mscorlib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch()    Unknown
        [Native to Managed Transition]

所有被阻止/阻塞的 session 都是定期更新，速度非常快，并且不会延迟客户端的数据库调用。我对每个数据库调用都使用 EF6 和 using(var db = new DB()) {...}。

阻塞其他连接的休眠连接可能出了什么问题？如何调试该问题？

最佳答案

今天刚遇到这个问题!我们的应用程序是一个网络应用程序，与您的情况相同，并且该网络应用程序在完成请求后错误地保持交易处于打开状态。然后它会坐在那里等待下一个请求，同时锁定数据库。

在 SQL 代码中需要检查的两件事可能会导致此问题:

(1) 确保所有 BEGIN TRANSACTION 语句末尾都有相应的 COMMIT TRANSACTION。否则，您的应用在等待下一个用户请求时可能会错误地保持事务打开。

(2) 检查 THROW 的所有使用，以查看事务内部是否有任何 THROW 语句。如果你想在事务期间抛出错误，你首先必须在THROW之前ROLLBACK TRANSACTION，否则SQL Server将使事务保持打开状态并锁定数据库。

关于sql-server - SQL Server `sp_who2` 过程显示 sleep 连接的长锁，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44734662/

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