InvalidOperationException: Timeout expired. The timeout period elapsed
prior to obtaining a connection from the pool. This may have occurred
because all pooled connections were in use and max pool size was
reached.
For some reason i usually get this error message once in awhile when testing locally
"DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=myDatabase;Trusted_Connection=True;"
Just when i pressed log in and where it does the check in database, it just takes forever until it gives me the exception with the error i just posted. Why does this happen? I think this hasn't happened on the production server yet or i just missed it, but would be nice to know why this happens.
Related
I have a .Net 6 webapplication, that is hosted in IIS on Windows server 2019.
Sometimes after deployment, it will start having issues connection to SQL server and WCF services.
The thing that strikes me is that both types of errors start appearing at the same time. The SQL server, net.tcp WCF services and HTTP WCF services all start throwing these errors at the same time.
This leads me to think it could be some kind of socket exhaustion or similar?
How would I diagnose this kind of broad connection issue?
Note: The application has been ported from .Net Framework to .Net 6, and the old version does not exhibit this behavior, so I suspect that the .Net 6 code has some sort of leak, but I need to find out what is causing it.
Examples of the exceptions:
SQL error after the default 15s timeout:
Begin failed with SQL exception Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached.
Another sql error
could not execute batch command.[SQL: SQL not available] Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. The wait operation timed out.
WCF net.tcp service
The socket was aborted because an asynchronous receive from the socket did not complete within the allotted timeout of 10675199.02:48:05.4775807. The time allotted to this operation may have been a portion of a longer timeout. The socket connection has been disposed.
Object name: 'System.ServiceModel.Channels.SocketConnection'.
HTTP HTTP service
The request channel timed out attempting to send after 00:01:00. Increase the timeout value passed to the call to Request or increase the SendTimeout value on the Binding. The time allotted to this operation may have been a portion of a longer timeout. The HTTP request to 'https://www.example.com/service' has exceeded the allotted timeout of 00:01:00. The time allotted to this operation may have been a portion of a longer timeout.
I am getting weird issue when i change deployment environment to my old ASP.net application . I migrated my ASP.net application from IIS 7 (windows server 2008 ) to IIS 8 (windows server 2012) ,application is running very well on old server but on new server i sometime get weird timeout issue . i have searched for my problem but i think i am the first one who is getting this issue :( . I even cant figure out, is this issue related to IIS timeout /session timeout or SQL timeout .
Time-out has expired. The time-out period has expired before a connection was obtained from the group. A possible cause is that all connections in the group have been in use and the maximum group was reached.
It looks like you have an application that isn't properly closing or disposing of the SqlConnection objects. By default, SqlConnection has a max pool size of 100.
The fix here would be to work with the application to find out why connections aren't being cleaned up, as they are still "active" in the particular connection pool, which is why you are unable to grab another one, because there are no inactive connections in the pool to use.
The application should be making a call to SqlConnection.Close() or SqlConnection.Dispose() in order to release the connection and mark it as "inactive".
While checking SystemOut.log during a reported slowness in the application I found StaleConnectionException occuring frequently. This exception was not observed earlier and I doubt that if this is the reason for slowness and needs to be resolved.
StaleConnectionException usually happens, when WebSphere was disconnected from the database. It can be caused by database restart or by network issue e.g. firewall which disconnects requests after some time. If it happens frequently, make sure that Purge policy for that datasource is set to Entire Pool, not Failing Connections. If you have firewall between WAS and DB set Aged timeout to lower value than timeout on firewall (try with 1200 for example).
Can this be a reason for slowness?
It can a bit, as when application gets StaleConnectionException, that request is failing and either application has implemented logic to retry it or end user will get error and will retry the same request.
In our production environment, we have a WCF serivce that is very frequently called.
We noticed that sometimes, calls to this service (only this one) fail on timeout for a period of time, after everything falls into place and the service responds correctly again.
I used Dynatrace to try to understand what's happening, I noticed that for the calls resulting on a timeout, the method of the service is never called ! And at the same time the server throw this error
A blocking operation was interrupted by a call to
WSACancelBlockingCall
and the client throws a Timeout Exception.
I want to understand the cause of this errors. Is the server error caused by the client's TimeoutException (when the client close its connection) ? Otherwise why do the server throw this error ?
Can you attach a screenshot of that PurePath?
The TimeoutException is simply thrown by the caller of a service when the called web services doesnt return within the default timeout - typically something like 60s. And - once the client aborts its network connection it will cause the exception in the server who has accepted that connection.
There can be multiple reasons for this slow behavior, e.g: you are maxing out the number of connections you have in your client - or the server implementation is overloaded and cant handle incoming requests. Definitely look at the number of worker threads/connections configured on both sides
If you want specific help on dynatrace freel free to send over the PurePaths - check out http://bit.ly/sharepurepath
hope this helps
I am running a load test in order to see the performance of the WCF services during the peak time (heavy load). I am using the Step-Load where we push the virtual users Step-by-Step. When I start running the load test for the first few minutes the test runs smoothly and as the load increases by time, after some time all of a sudden the below error is triggering,
"Test method "XYZ" threw exception:
System.ServiceModel.CommunicationException: The socket connection was aborted. This could be caused by an error processing your message or a receive timeout being exceeded by the remote host, or an underlying network resource issue. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host".
I tried lot of solution that I found online but non of them worked for me. I tried changing the default time-outs, maxconnections, maxconcurrent connections etc., in config files. I would really appreciate any help on this.
I had similar problems while ago when moved to WCF. It have probably something to do with the way WCF handles connections.
Solution for me was to move each test into separate ApplicationDomain.