在负载下带有.Net Core容器的SQL Server DbCommand超时 [英] SQL Server DbCommand Timeout with .Net Core container under load

问题描述

我正在Open Shift Enterprise V3上运行一个指向SQL Server数据库的.Net Core容器.

I'm running a .Net Core container on Open Shift Enterprise V3 pointing to a SQL Server database.

我有一个带有put方法的.Net Core REST API，该方法可以添加或更新数据库中的记录.

I have a .Net Core REST API with a put method which adds or updates a record in the database.

我要添加/更新的表具有3000条记录并具有索引.

The table I am adding/updating had 3000 records and has indexes.

使用相同的数据库和容器在本地可以正常工作.但是，当我开始通过容器加载负载时(与JMeter大约有50个并发的HTTP连接)，我收到随机超时，并出现以下错误消息.我没有在本地运行的问题.

This works fine locally using the same database and with the container. However when I start to put load through the the container (approximately 50 concurrent http connections with JMeter) I get random timeouts with the error message below. I don't get the problem running locally.

本地计算机比容器功能强大得多，我提高了容器上的CPU能力，但这似乎没有任何区别.

The local machine is a lot more powerful than the container and I have increased the CPU power on the container but this doesn't appear to have made any difference.

任何有关尝试的建议都会受到赞赏.

Any suggestions on things to try would be appreciated.

[10:45:36 ERR] Failed executing DbCommand (35,001ms) [Parameters=[@__get_Item_0='?' (Size = 255) (DbType = AnsiString)], CommandType='Text', CommandTimeout='30']
SELECT [e].[host_name], [e].[data_centre], [e].[Environment], [e].[is_physical_machine], [e].[mac_address], [e].[number_of_cores], [e].[number_of_sockets], [e].[number_of_v_cores], [e].[number_ofcpus], [e].[operating_system], [e].[operating_system_version], [e].[processor], [e].[uuid]
FROM [EntitlementServer].[host] AS [e]
WHERE [e].[host_name] = @__get_Item_0
System.Data.SqlClient.SqlException (0x80131904): Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding. ---> System.ComponentModel.Win32Exception (258): Unknown error 258
   at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 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.SqlDataReader.TryConsumeMetaData()
   at System.Data.SqlClient.SqlDataReader.get_MetaData()
   at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
   at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)
   at System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteReader()
   at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.Execute(IRelationalConnection connection, DbCommandMethod executeMethod, IReadOnlyDictionary`2 parameterValues)
ClientConnectionId:6ca037fc-9671-4d43-bebe-35879203c682
Error Number:-2,State:0,Class:11

更新1

尽管我发现扩展容器上的CPU和内存对性能没有帮助.当我增加正在运行的容器的数量时，确实增加了吞吐量，并且超时问题消失了.我不知道为什么会这样.

Whilst I found that scaling up the CPU and memory on the container did not help with performance. When I increased the number of running containers, that did increase throughput and the timeout issue went away. I am not sure why this would be the case.

推荐答案

该问题实际上是一个线程问题.数据库超时是一种症状.这就是为什么增加容器数可以解决此问题的原因，因为http线程数也有所增加.

The problem actually turned out to be a threading issue. The db timeout was a symptom. This is the reason why increasing the number of containers stopped the problem because the number of http threads also increased.

通过使代码异步以便释放线程，我能够解决该问题，而不必增加容器的数量.

By making code asynchronous so that threads are released I have been able to fix the problem without having to increase the number of containers.

这篇关于在负载下带有.Net Core容器的SQL Server DbCommand超时的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！