entity-framework - Sql Azure 的暂时性错误

Question

我们有以下 DB 配置设置，但是在针对 SQL Azure(P1 层)操作时，我们仍然看到大量的瞬时错误通知。

public class DbConfiguration : System.Data.Entity.DbConfiguration
{ public DbConfiguration()
{
SetExecutionStrategy("System.Data.SqlClient", () => new SqlAzureExecutionStrategy(5, TimeSpan.Parse("00:00:03"));
}
}
任何熟悉这一点的人都可以评论我们可能设置不正确的任何内容吗？我们正在使用 EF6。

我们得到的确切异常(exception)是:

An exception has been raised that is likely due to a transient failure. If you are connecting to a SQL Azure database consider using SqlAzureExecutionStrategy. Exception Full Value: System.Data.Entity.Core.EntityException: An exception has been raised that is likely due to a transient failure. If you are connecting to a SQL Azure database consider using SqlAzureExecutionStrategy. ---> System.Data.Entity.Core.EntityException: The underlying provider failed on Open. ---> System.Data.Entity.Core.EntityException: An exception has been raised that is likely due to a transient failure. If you are connecting to a SQL Azure database consider using SqlAzureExecutionStrategy. ---> System.Data.SqlClient.SqlException: A connection was successfully established with the server, but then an error occurred during the login process. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.) ---> System.ComponentModel.Win32Exception: An existing connection was forcibly closed by the remote host --- End of inner exception stack trace --- at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action1 wrapCloseInAction)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
at System.Data.SqlClient.TdsParserStateObject.ReadSniError(TdsParserStateObject stateObj, UInt32 error)
at System.Data.SqlClient.TdsParserStateObject.ReadSniSyncOverAsync()
at System.Data.SqlClient.TdsParserStateObject.TryReadNetworkPacket()
at System.Data.SqlClient.TdsParserStateObject.TryPrepareBuffer()
at System.Data.SqlClient.TdsParserStateObject.TryReadByte(Byte& value)
at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlInternalConnectionTds.CompleteLogin(Boolean enlistOK)
at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover)
at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)
at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)
at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData)
at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions) at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource1 retry)
at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource1 retry) at System.Data.SqlClient.SqlConnection.Open() at System.Data.Entity.Infrastructure.Interception.InternalDispatcher1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action2 operation, TInterceptionContext interceptionContext, Action3 executing, Action3 executed) at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext) at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass1.b__0() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 operation)
--- End of inner exception stack trace ---
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 operation) at System.Data.Entity.Core.EntityClient.EntityConnection.Open() --- End of inner exception stack trace --- at System.Data.Entity.Core.EntityClient.EntityConnection.Open() at System.Data.Entity.Core.Objects.ObjectContext.EnsureConnection(Boolean shouldMonitorTransactions) at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass471.b__45() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 operation)
--- End of inner exception stack trace ---
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 operation) at System.Data.Entity.Core.Objects.ObjectContext.ExecuteFunction[TElement](String functionName, ExecutionOptions executionOptions, ObjectParameter[] parameters)

Answer 1

由于以下原因(不是详细列表..)，Azure 中出现暂时性错误

1.您的数据库负载过重(用完所有/达到dtu配额)

使用下方 DMV 查看 DTU 指标

SELECT 
    (COUNT(end_time) - SUM(CASE WHEN avg_cpu_percent > 80 THEN 1 ELSE 0 END) * 1.0) / COUNT(end_time) AS 'CPU Fit Percent'
    ,(COUNT(end_time) - SUM(CASE WHEN avg_log_write_percent > 80 THEN 1 ELSE 0 END) * 1.0) / COUNT(end_time) AS 'Log Write Fit Percent'
    ,(COUNT(end_time) - SUM(CASE WHEN avg_data_io_percent > 80 THEN 1 ELSE 0 END) * 1.0) / COUNT(end_time) AS 'Physical Data Read Fit Percent'
FROM sys.dm_db_resource_stats

2.如果你看到DTU的使用在暂时性故障的时候是正常的，但仍然看到错误，看看是否有优化的机会。和统计

3. 联系 Azure 支持并提供故障时间戳，看看是否有任何维护事件