I'm using LINQ to SQL to access a stored procedure. This works fine on my local sql server. But once I point to a different server within the internal network, I get a timeout. In SQL Profiler, I can see the query that is sent to the problem server. This should mean the query is hitting the server and executing right?
I can run the LINQ output directly on the problem server without issue. Is this probably not a code issue and instead some problem with the sql server server configuration? What should I check to troubleshoot it?
The connect timeout is different from the command timeout.
see: What is the difference between SqlCommand.CommandTimeout and SqlConnection.ConnectionTimeout?
The summary is connect timeout is the amount of time to establish a connection.
Command timeout is the amount of time to let the command run. Not just how long it takes to get the first record, but how long it takes to grab the entire dataset.
If you see the query showing up in SQL Profiler, then yes it is being sent. So you're essentially hitting the command timeout default limit of 30 seconds.
I would suggest starting with changing the command timeout to 500 and see where that takes you. Then I would start doing some performance analysis to determine why it takes that long. Maybe you can trim out some of the data requested or even add additional indexes to better support the query.
Related
My C# application is currently throwing lots of the below exceptions:
Timeout expired. The timeout period elapsed prior to completion of
the operation or the server is not responding. This failure occurred
while attempting to connect to the routing destination.
I am using linq queries and NHibernate.
I am having difficulty troubleshooting this as the exception does not occur every time the query is ran. If I take the query and run it directly on SSMS it seems to run very quickly.
The timeout exceptions only appear to occur when ran against one table in the database.
I know I am able to increase the query timeout but I would like to resolve the root cause of the issue. I have a limited knowledge in troubleshooting these issues so what are the next steps I need to take to determine what the problem is?
Increase 'Connect Timeout' of your connection string. 60 is a good number.
Currently I'm experiencing alot of issues with Server Processes (Seen from sp_who2) that is "sleeping" instead of just, finishing (being removed), when I connection to my MSSQL Database, calls a Stored Procedure, get some data and then closing the connection.
What's the best way in C#/.NET to connect to a MSSQL database, call a Stored Procedure, retrieve data from the Stored Procedure (Data Reader) and then close the connection?
Is there a way to close/dispose so that the "sleeping" processes gets killed?
Does it have something to do with me creating new SqlConnections, opening them and closing them all the time?
My flow is as follows:
A request occur:
I create a new SqlConnection Instance that connects to my MSSQL Database.
I call a Stored Procedure, retrieve the data and presents it to the user.
I close the Connection with .Close();
I repeat all these steps for each request. Requests happen once every 5-10 seconds. (Sometimes slower, sometimes faster)
I'm sorry If this question is missing some details, but I hope this is enough to get a some what helpful answer.
Thanks!
you need to use SET XACT_ABORT ON or add some client rollback code
When a client timeout event occurs (.net CommandTimeout for example), the client sends an "ABORT" to SQL Server. SQL Server then simply abandons the query processing. No transaction is rolled back, no locks are released.
Now, the connection is returned to the connection pool, so it isn't closed on SQL Server. If this ever happens (via KILL or client reboot etc) then the transactions+locks will be cleared. Note that sp_reset_connection won't or doesn't clear them, even though it is advertised to do so
This detritus from the abort will block other processes.
The way to make SQL Server clear transactions+locks on client timeout (strictly, ABORT events) is to use SET XACT_ABORT ON.
You can verify this be opening 2 query windows in SSMS:
Window 1:
In menu Query..Query Options set a timeout of 5 seconds then run this
BEGIN TRAN
UPDATE sometable WITH (TABLOCKX) SET foo = foo WHERE 1 = 0;
WAITFOR DELAY '00:00:10' -- just has to be longer then timeout
Window 2, this will wait forever (or hit your timeout)
SELECT * FROM sometable
I have an SQL Server (2008 R2) based (C# WinForms) application that predominantly runs on a local machine using a local installation of SQL Server 2008 R2. One problem I have is that if the user does not have a server instance running and tries to execute some commands or perform some operations, the queries are sent off to SQL Server and it takes an age to throw an SqlException telling me the requested instance is not started.
I have read the following question and associated answers, but these solutions are far from ideal. WMI seem very much over-kill and I do not want to have to include extra .dlls in my installation package for the software if it can be avoided.
I have also come accross the SqlDataSourceEnumerator Class documented here
// Retrieve the enumerator instance and then the data.
SqlDataSourceEnumerator instance = SqlDataSourceEnumerator.Instance;
System.Data.DataTable table = instance.GetDataSources();
which dumps the available connection into a DataTable. However, there seems to be inherent problems with returning all the available connections:
"All of the available servers may or may not be listed. The list can vary depending on
factors such as timeouts and network traffic. This can cause the list to be different
on two consecutive calls." - MSDN.
There has to be a set way of dealing with this problem. Say I have the following SqlConnection string:
Data Source=localhost;Initial Catalog=MyDB;Integrated Security=True;Connection Timeout = 0
what can I use as an efficient (this is crucial) check as to whether the selected instance ('localhost' [the default instance] or 'SomeInstanceName') is running?
Thanks for your time.
I don't think you need to worry about timeouts or network issues when the server and client are the same machine. Just attempting to connect is about efficient as you're going to get, the crucial part is going to be how long do you let the connection attempt try before you give up (connection timeout). You can shorten that window obviously, but if you make it too short, then the problem doesn't really make sense.
You can change the connection timeout to be a shorter period, but essentially, the only way it knows that a server isn't there, is from a timeout.
Any technique you use will likely have the exact same timeout issue.
If you know the instance name, such as "MSSQL$InstanceName" you can use the System.ServiceProcess.ServiceController class to get a list of all services on the machine and then loop through looking to see if any ServiceName == MSSQL$InstanceName.
I have found this to be very fast plus you can check to see if it is running and start it if it is not running.
You could try opening up a simple TCP connection to the standard SQL port and see if it sticks .
set the connection timeout to some reasonably low value based on your environment.
see
http://support.microsoft.com/kb/287932
for sql serevr port numbers.
I'm looking for a way to check if a server is still available.
We have a offline application that saves data on the server, but if the serverconnection drops (it happens occasionally), we have to save the data to a local database instead of the online database.
So we need a continues check to see if the server is still available.
We are using C# for this application
The check on the sqlconnection.open is not really an option because this takes about 20 sec before an error is thrown, we can't wait this long + I'm using some http services as well.
Just use the System.Net.NetworkInformation.Ping class. If your server does not respond to ping (for some reason you decided to block ICMP Echo request) you'll have to invent your own service for this. Personally, I'm all for not blocking ICMP Echo requests, and I think this is the way to go. The ping command has been used for ages to check reachability of hosts.
using System.Net.NetworkInformation;
var ping = new Ping();
var reply = ping.Send("google.com", 60 * 1000); // 1 minute time out (in ms)
// or...
reply = ping.Send(new IPAddress(new byte[]{127,0,0,1}), 3000);
If the connection is as unreliable as you say, I would not use a seperate check, but make saving the data local part of the exception handling.
I mean if the connection fails and throws an exception, you switch strategies and save the data locally.
If you check first and the connection drops afterwards (when you actually save data), then you still would still run into an exception you need to handle. So the initial check was unnecessary. The check would only be useful if you can assume that after a succesfull check the connection is up and stays up.
From your question it appears the purpose of connecting to the server is to use its database. Your priority must be to check whether you can successfully connect to the database. It doesn't matter if you can PING the server or get an HTTP response (as suggested in other answers), your process will fail unless you successfully establish a connection to the database. You mention that checking a database connection takes too long, why don't you just change the Connection Timeout setting in your application's connection string to a more impatient value such as 5 seconds (Connection Timeout=5)?
If this is an sql server then you can just try to open a new connection to it. If the SqlConnection.Open method fails then you can check the error message to determine if the server is unavailable.
What you are doing now is:
use distant server
if distant server fails, resort to local cache
How to determine if the server is available? Use a catch block. That's the simplest to code.
If you actually have a local database (and not, for example, a list of transactions or data waiting to be inserted), I would turn the design around:
use the local database
regularly synchronize the local database and the distant database
I'll let you be the judge on concurrency constraints and other stuff related to your application to pick a solution.
Since you want to see if the database server is there either catch any errors when you attempt to connect to the database or use a socket and attempt a raw connection to the server on some service, I'd suggest the database as that is the resource you need.
I am using Asp.Net c# and Sql Server 2005. I am using Masterpage and content page. when i debug my code that time it's give error ::
Window Internet Explorer
SYS.WEBFORMS.PAGEREQUESTMANAGER TIMEOUTEXCEPTION: THE SERVER REQUEST TIMED OUT.
Any body please help me out ?
Thanks
It is an Ajax error - do you only get the error when debugging? If you want to increase this timeout then set the AsyncPostBackTimeout of your script manager to something large
You have an ajax request that's taking too long to complete. It would help if you can isolate the request and share what it's trying to do.
This happens if you sit there too long trying to step through your ajax request. Either increase the timeout or work faster.
Incidentally, I believe the timeout setting defaults to 90 seconds. See this for more information.
I don't see anything immediately obvious in that error message to suggest it's a SQL server request that's timing out rather than any other sort of "server request". However, if it is, stick a profiler on your SQL server to see which request is taking a long time - and find out whether it's just a query which needs speeding up, a deadlock, or something like that.
Another possibility is that it's the connection pool - if you're not closing your connections properly, you could be timing out waiting for them to be returned to the pool. If that's the case, you obviously won't see the request in the SQL profiler.