问题
I have application running on my server. The problem with this application is that daily I am getting nearly 10-20, System.Data.SqlClient.SqlException Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding only one of my SP. Here is my SP,
ALTER PROCEDURE [dbo].[Insertorupdatedevicecatalog]
(@OS NVARCHAR(50)
,@UniqueID VARCHAR(500)
,@Longitude FLOAT
,@Latitude FLOAT
,@Culture VARCHAR(10)
,@Other NVARCHAR(200)
,@IPAddress VARCHAR(50)
,@NativeDeviceID VARCHAR(50))
AS
BEGIN
DECLARE @OldUniqueID VARCHAR(500) = '-1';
SELECT @OldUniqueID = [UniqueID] FROM DeviceCatalog WHERE (@NativeDeviceID != '' AND [NativeDeviceID] = @NativeDeviceID);
BEGIN TRANSACTION [Tran1]
BEGIN TRY
IF EXISTS(SELECT 1 FROM DeviceCatalog WHERE [UniqueID] = @UniqueID)
BEGIN
UPDATE DeviceCatalog
SET [OS] = @OS
,[Location] = geography::STGeomFromText('POINT(' + CONVERT(VARCHAR(100 ), @Longitude) + ' ' + CONVERT(VARCHAR(100), @Latitude) + ')', 4326)
,[Culture] = @Culture
,[Other] = @Other
,[Lastmodifieddate] = Getdate()
,[IPAddress] = @IPAddress
WHERE [UniqueID] = @UniqueID;
END
ELSE
BEGIN
INSERT INTO DeviceCatalog
([OS]
,[UniqueID]
,[Location]
,[Culture]
,[Other]
,[IPAddress]
,[NativeDeviceID])
VALUES (@OS
,@UniqueID
,geography::STGeomFromText('POINT(' + CONVERT(VARCHAR(100) ,@Longitude) + ' ' + CONVERT(VARCHAR(100), @Latitude) + ')', 4326)
,@Culture
,@Other
,@IPAddress
,@NativeDeviceID);
IF(@OldUniqueID != '-1' AND @OldUniqueID != @UniqueID)
BEGIN
EXEC DeleteOldDevice @OldUniqueID, @UniqueID;
END
END
COMMIT TRANSACTION [Tran1];
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION [Tran1];
DECLARE @ErrorNumber nchar(5), @ErrorMessage nvarchar(2048);
SELECT
@ErrorNumber = RIGHT('00000' + ERROR_NUMBER(), 5),
@ErrorMessage = @ErrorNumber + ' ' + ERROR_MESSAGE();
RAISERROR (@ErrorMessage, 16, 1);
END CATCH
END
Is there is any issue with this SP? Why I am getting Timeout exception only in this SP? Here is the Stack Trace,
System.Data.SqlClient.SqlException (0x80131904): Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
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)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
at App.Classes.DBLayer.Execute(SqlCommand command, Boolean executeNonQuery)
at App.Helpers.SQLHelper.GetResult(List`1 parameters, Boolean storedProcedure, String commandText, ResultType type)
at App.Helpers.SQLHelper.ExecuteNonQuery(List`1 parameters, Boolean storedProcedure, String commandText)
at App.Services.DeviceCatalogService.InsertOrUpdateDeviceCatalog(DeviceCatalog deviceCataLog)
at WebApplication1.Handlers.RegisterDevice.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
回答1:
You need to investigate this on the server side to understand why is the execution timing out. Note that the server has no timeout, the timeout is caused by the default 30 seconds on SqlCommand.CommandTimeout.
A good resource is Waits and Queues, which is a methodology to diagnose performance bottlenecks with SQL Server. Based on the actual cause of the timeout, proper action can be taken. You must establish first and foremost whether you're dealing with slow execution (a bad plan) or blocking.
If I'd venture a guess, I would say that the unhealthy pattern of IF EXISTS... UPDATE is the root cause. This pattern is incorrect and will cause failures under concurrency. Two concurrent transaction executing the IF EXISTS simultaneously will both reach the same conclusion and both attempt to INSERT or UPDATE. Depending on the exiting constraints in the database you can end up with a deadlock (the lucky case) or with a lost write (the unlucky case). However, only proper investigation would reveal the actual root cause. Could be something totally different, like auto-growth events.
Your procedure is also incorrectly handling the CATCH block. You must always check the XACT_STATE() because the transaction may be already rolled back by the time your CATCH block runs. Is also not clear what you expect from naming the transaction, this is a common mistake I see often associated with confusing named transactions with savepoints. For a correct pattern see Exception Handling and Nested Transactions.
Edit
Here is a possible way to investigate this:
- Change the relevant CommandTimeout to 0 (ie. infinite).
- Enable the blocked process threshold, set it to 30 seconds (the former CommandTimeout)
- Monitor in Profiler for Blocked Process Report Event
- Start your workload
- See if the Profiler produces any report events. If it does, they will pinpoint the cause.
These actions will cause a 'blocked process report' event every time you would had get a timeout, if the timeout was cause by blocking. You application will continue to wait until the blocking is removed, if the blocking is caused by a live-lock then it will wait forever.
回答2:
Add this line to your connection string:
Connect Timeout=200; pooling='true'; Max Pool Size=200
You can set myCom.CommandTimeout = 200 also
If large number of data is there you can also increase the timeout seconds from 200 to 600 seconds.
Edit this in web.config as well.
Follow THIS doccument.
回答3:
This can happens because of parameter sniffing. So just use local variables, declared within the stored proc. and use them appropriately.
Declare @InVar1 ...
.....
where condition=@Invar1
回答4:
Maybe the OPTIMIZE FOR or WITH RECOMPILE hints solve the SQL Exception Timeout problem.
This article teachs how to implement it and explains the "parameter sniffing" issues:
https://blogs.msdn.microsoft.com/robinlester/2016/08/10/improving-query-performance-with-option-recompile-constant-folding-and-avoiding-parameter-sniffing-issues/
来源：https://stackoverflow.com/questions/16917107/occasionally-getting-sqlexception-timeout-expired