My SignalR server (ASP.NET) and client (ASP.NET) both are working fine as excepted but multiple times on a daily basis, I'm getting the following two errors at the end of the SignalR client (ASP.NET):
System.Net.Sockets.SocketException (0x80004005): An existing connection was forcibly closed by the remote host
System.Net.WebException: The request was aborted: The connection was closed unexpectedly.
I've looked in the following ways but still unable to find out the root cause
Check High CPU usage when the error occurred.
Tried to send lots of data to the Server but received all the data received successfully at the Client through the Server.
Checked server is not creating unnecessary connections. Only max three connections are there.
Related
Working on a client application (running on windows) problem which uses asynchronous communication (with sockets) with the database server (running on linux).
The client application hit with WSAECONNRESET error while loading data to the server and the server terminates the socket. I have used the WSAGetLastError function and extracted the error message. The server had send some messages (reporting application specific error message) to the client before terminating the socket with WSAECONNRESET error. The client is unable to extract the last message which is sent by the server (as the socket is closed and "recv" function fails). My question is how to extract the last messages sent by the database server (on linux) to client(on windows) ?
Please note, this case is working fine with linux database server to linux client. I mean, unix socket to unix socket. But problem occurs only with linux socket to windows socket communication.
Appreciate your help Please !!
You can't. 'Connection reset' destroys the connection, and all in-flight data is lost, including any that may be already buffered at the receiver.
You need to fix the problem that causes the reset.
I've been testing a website in Azure for about a month (Free trial), and now I've subscribed to pay-as-you-go. When I was on the free trial, I had absolutely no connectivity issues. Now I've deployed again to a fresh website created on the pay-as-you-go subscription with the same settings (scaling mode etc.) as the previous one. However, now when I navigate to my site, it sometimes fails to connect to my database:
Server Error in '/' Application.
A connection attempt failed because the connected party did not properly respond after
a period of time, or established connection failed because connected host has failed to
respond
Description: An unhandled exception occurred during the execution of the current web
request. Please review the stack trace for more information about the error and where
it originated in the code.
Exception Details: System.ComponentModel.Win32Exception: A connection attempt failed
because the connected party did not properly respond after a period of time, or
established connection failed because connected host has failed to respond
Source Error:
An unhandled exception was generated during the execution of the current web request.
Information regarding the origin and location of the exception can be identified using
the exception stack trace below.
Stack Trace:
[Win32Exception (0x80004005): A connection attempt failed because the connected party
did not properly respond after a period of time, or established connection failed
because connected host has failed to respond]
[SqlException (0x80131904): A network-related or instance-specific error occurred
while establishing a connection to SQL Server. The server was not found or was not
accessible. Verify that the instance name is correct and that SQL Server is configured
to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt
failed because the connected party did not properly respond after a period of time, or
established connection failed because connected host has failed to respond.)
I try to refresh the page and it connects. After a few minutes, when I try again, I sometimes get the same error again, but sometimes not. I never had a single connectivity issue in the free trial mode. Why does it happend and how can I prevent this problem?
Transient errors are expected in a cloud environment. Let's say that a database call fails, if you retry a few milliseconds later, that same call would now work. To shield you from these errors, you need to implement a retry logic. If you use Entity Framework 6, you're in luck since it's baked in: http://msdn.microsoft.com/en-US/data/dn456835
Here's a quick video on how to implement this: http://www.azurerocks.com/0_oaw-merMw
You can also use the Enterprise Library Transient Fault Handling Application Block: http://msdn.microsoft.com/en-us/library/hh680934(v=pandp.50).aspx
I've been having some connectivity issues recently with my website. And today I finally received SOME idea as to what the issue may be. I got this error message while trying to log in.
A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)
So the question is, what could be causing this error message to get generated?
This only ever seems to occur under high user load. CPU, RAM, and network traffic do not seem to be maxed out.
This error very very often occurs straight after you have had a connection break (e.g. the server terminated the connection, your server process had the KILL command run against it or the network connection between you and the server was broken), and especially if your client is using connection pooling in those circumstances.
So try looking at what happened prior to the error you're seeing.
I have an application that is used to make hotel bookings. The application takes an XML message, transforms the XML into another XML message and sends this new XML to another application. I am able to book hotels successfully.
When I try to amend this booking (different XML request, same application, same URL) I get a 'Connection refused' error.
I would have thought that there'd be consistency (all work or none) but there's not.
Anyone any idea why?
"Connection refused" means that no application is accepting connections on the port and host that you try to connect to. It can be caused by
The application is actually running on a different host or a different port
The application crashed and hasn't been restarted
The application is buggy: it closes the listening server socket from time to time, so that it is not listening for connection attempts all the time
Firewall is configured to respond to new connections with a "connection refused" even if the application was able to accept a connection
Background
We have a number of web applications on different web servers that connect to a single database server. Over the past couple months, we have noticed that every once in awhile, our web servers won't be able to connect to the database server.
Our Environment
We have a couple different web environments, some running ColdFusion and others running .NET. The .NET apps are both Web Forms and MVC. They span multiple versions from 2.0 to 4.5. Both the ColdFusion and .NET web servers are windows based machines. Both the ColdFusion and .NET web environments are clustered and some of the machines are physical while others are virtual.
Our database server is SQL Server 2008 r2. It houses multiple databases. Each application has its own database user that it connects with to the server that only gives it access to a particular database.
Other Facts
When we notice issues, they occur in short bursts that last anywhere from a couple seconds to a couple minutes.
When we notice issues, the burst contains errors from multiple different appliations, not just one app at at time.
When we notice issues, the burst contains errors from applications from different web environments. (This makes us think we can rule out that the apps themselves are the issue)
The burst of connection issues happen at various times throughout the day and night. They are not always during times of high usage.
We have monitored things like number of user connections, memory, IO, CPU usage, etc... and we have not seen spikes or anything else that might point to a problem.
We have installed wireshark on the web and db servers in hopes of catching the problem without any success.
Questions
Does anyone have suggestions on where I should look next?
Are there properties of the database that could cause this?
Is there any way to "monitor" the connection between the database and web server in a better manner?
Is there anything that can be done on the app side to better understand what is happening?
Errors Caught by Apps
.NET errors
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)
Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.)
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.
ColdFusion errors
Error Executing Database Query. The TCP/IP connection to the host has failed. java.net.ConnectException: Connection timed out: connect The error occurred on line 38.
Error Executing Database Query. Connection reset by peer: socket write error The error occurred on line 91.
Error Executing Database Query. Timed out trying to establish connection The error occurred on line 38.
In CF, I once had an issue like what you were seeing. I had CF on 1 server, and sql 2008 r2 on another server. I would see CF errors like you posted below. To help trace it to a network error I wrote something like this:
1) created a down.bat
tracert serverip
2) I then put a <cftry><cfcatch> around the query.
When the query generated the error I would execute
<cfexecute name="C:\path\to\down.bat" variable="log" timeout="60" />
<cfmail to="ME" from="Server" subject="SQL DOWN">
Server Debugging Info:
------------------------------------------------------------
#now()#
#cfcatch.Detail#
#cfcatch.Message#
#log#
</cfmail>
</cfexecute>
This helped me fix my situation which ended up being hardware at the datacenter.