Not sure if this is the correct forum for this, but here goes.
Im looking for any suggestions as to what I can try to reslove this...
I have an Access 2003 front end (on each client) with SQL 2008 database. Ive went round each user and set up the odbc connection on each pc.
for most users its fine and been working well for a year, but for a few every now and then when running a query (either an update or a select when opening a form) the SQL connection seems to have been dropped and they cant go any further.
I cant think of any glaring difference between those who have it working and those who dont.
Any idea's where I should start with this?
thanks
I've had such cases before: Access frontend, SQL Server backend. On one or some of the customer's PCs, the connection suddenly drops (throwing some ODBC or SQL Server connection error). Happens randomly and rarely (e.g. once per hour/day/week), and the Access application needs to be restarted to continue working.
In all of these cases, one of the following was the culprit:
Broken network cable
Broken network card
Buggy network card driver
Unstable network protocol (yes, this one was in the old days of NetBIOS)
The thing is: Access is extremely sensitive to network errors. A simple glitch in the network, a few seconds of lost connectivity -- something which you won't even notice with other applications -- will cause an Access frontend application to lose its database connection and crash horribly. It's very frustrating, because the customer will say "I don't experience any network trouble with Word/Windows Explorer/etc., so my network is fine, and it's your application that's broken." It's not true. If Access experiences sporadic and unpredictabe network errors, it's usually really a network problem.
So, the first thing I'd do is to replace (a) the network card, (b) the network cable and (c) use another switch port for one of the machines experiencing problems. If the problems are gone on that machine, you know that one of these components was the faulty one.
Related
I'm trying to set up mirroring between two sql 2008 databases on different servers in my internal network, as a test run before doing the same thing with two live servers in different locations.
When I actually try and switch the mirroring on the target DB (with
ALTER DATABASE testdb SET PARTNER = N'TCP://myNetworkAddress:5022') I'm getting an error telling me that the server network address can not be reached or does not exist. A little research suggests this is a fairly unhelpful message that pops up due to a number of possible causes, some of which are not directly related to the server existing or otherwise.
So far I've checked and tried the following to solve this problem:
On the target server, I've verified that in SQL Configuration Manager that "Protocols for SQLEXPRESS" (my local installation is labelled SQLEXPRESS for some reason, even though querying SERVERPROPERTY('Edition') reveals that it's 64-bit Enterprise), and Client Protocols for SQL Native Client 10 all have TCP/IP enabled
I'm using a utility program called CurrPorts to verify that there is a TCP/IP port with the same number specified by the mirroring setup (5022) is open and listening on my machine. Netstat verifies that both machines are listening on this port.
I've run SELECT type_desc, port FROM sys.tcp_endpoints; and
SELECT state_desc, role FROM sys.database_mirroring_endpoints to ensure that everything is set up as it should be. The only thing that confused me was the "role" returns 1 .. not entirely sure what that means.
I've tried to prepare the DB correctly. I've taken backups of the database and the log file from the master DB and restored them on the target database with NORESTORE. I've tried turning mirroring on both while leaving them in the NORESTORE state and running an empty RESTORE ... neither seems to make much difference. Just as a test I also tried to mirror an inactive, nearly empty database that I created but that didn't work either.
I've verified that neither server is behind a firewall (they're both on the same network, although on different machines)
I've no idea where to turn next. I've seen these two troubleshooting help pages:
http://msdn.microsoft.com/en-us/library/ms189127.aspx
http://msdn.microsoft.com/en-us/library/aa337361.aspx
And as far as I can tell I've run through all the points to no avail.
One other thing I'm unsure of is the service accounts box in the wizard. For both databases I've been putting in our high-level access account name which should have full admin permissions on the database - I assumed this was the right thing to do.
I'm not sure where to turn next to try and troubleshoot this problem. Suggestions gratefully received.
Cheers,
Matt
I think that SQL Express can only act as a witness server with this SQL feature, you might get better mileage on ServerFault though.
Mike.
Your network settings might be OK. We got quite non-informative error messages in MS SQL - the problem might be an authorization issue and the server still will be saying "network address can not be reached".
By the way, how the authentication is performed? A MSSQL service (on server1) itself must be runned as a valid db user (on server2, and vice versa) in order to make the mirroring work.
I have a SQL Server 2008 database utilizing Filestreaming and all works fine and dandy apart from under one very strange circumstance. If i have my database on, say a laptop, on a locally installed version of SQL Server 2008 and am connected to the network all works fine. If i unplug the network cable, after a while the SqlFileStream class fails to initialize with a Win32 exception (everything else about connecting to the database works fine). If i start fresh without a network cable it will not work with the same error. If i plug a network cable in even with no network connectivity it works... take it out, nothing.
I'm connecting to the filestream in the usual documented method
SqlFileStream fileStream = new SqlFileStream(path,
context,
FileAccess.ReadWrite,
FileOptions.SequentialScan,
0);
geting the path and context from a stored procedure which generates them in the following
SELECT Data.PathName(), GET_FILESTREAM_TRANSACTION_CONTEXT()
FROM dbo.DocumentFiles
WHERE [File_ID] = #FileId
I'm getting the following error when creating the SqlFileStream instance
Win32Exception occurred The network
location cannot be reached. For more
information about network
troubleshooting, see Windows help.
No inner exception.
I have tried so many things to resolve the issue with no luck. no one in google-land seems to have the same issue so obviously something silly I'm doing. If anyone can shed any light on this i would be most grateful.
James
Hmm. It looks like your network interface goes down when you unplug your cable. When it happens TCP/IP stack goes down as well since there's no more available interfaces left. I suggest you to to install the MS Loopback adapter, this article explains how to do it in Windows XP; it is easy to google about how to do it in other OSes. Do not forget to assign a static IP to it after installation, private address like 192.168.1.x would be sufficient. Since loopback adapter is a virtual one, it is in "Up" state all the time, even when you unplug your cable and it prevents Windows from shutting TCP stack down.
Provide Used: Microsoft OLE DB Provider for SQL Server. Can anyone help me with this..
I was trying to connect with LLBLgen
This MSDN blog page has some useful on this...
http://blogs.msdn.com/sql_protocols/archive/2006/12/02/understanding-kerberos-and-ntlm-authentication-in-sql-server-connections.aspx
In my case, I found the account was locked.
Reason was I previously, on another machine more than 3 times tried to login.
It did not recognise me - and tthen finally it locked my account.
Reopening account made all work fine.
br
Jan
The error you get is almost always caused by a problem with using Windows Authentication. Please try switching to a SQL server login (username/password), or make sure your current Windows login has access to the SQL server and database you're trying to connect to.
-Edoode
I fixed this by mapping a drive to the server running MSSQL. This seemed to generate some kind of trust that allows MSSQL to connect without this error even after a reboot.
I used to get this error sometimes when connecting to my local SQL Server with Windows Authentication. I never fixed it unfortunately - it went away when I reinstalled windows.
I think a reboot used to fix it - have you tried that? Not exactly the best solution, I know :P
Try to synchronize your date and time with the your domain's. The SSPI issue may be related to Active Directory authentication problems, some of them related to date and time changes. This is very simple to check and fix. Try it out!
There is a Microsoft KB article that addresses many of the reasons for this area (KB811889) at the following URL: http://support.microsoft.com/kb/811889.
A lot of Googling shows that one of the diagnostic steps helped most people who encountered the issue.
I recently had this exact issue where I'd get this error only when authenticating with certain accounts, but not others. Ultimately what was causing my problem was not mentioned in any KB or article I found on the net, but through trial and error I discovered that when the account used through SSPI authentication to SQL Server (2k8) happened to be in a large number of groups (in my case over 250) you would get the "Cannot Generate SSPI context" error. I suspect it has something to do with overflowing the security token that Kerberos uses and have seen similar strange authentication problems for user accounts in a large number of groups.
I get the problem when I have the time set differently on my client machine than either the server or the AD machine ( I was trying to test into the future).
Short Answer: Have you recently change the user the service is running as? Was there a system crash?
Long Answer:
I know this is old, but I want to post my experience that I just had.
We had spent hours Googling and found nothing that worked.
Eventually we ran across a set of actions that could cause this:
If you change the user that the Sql Server runs as (e.g. from Local System to a domain usr) and do certain updates and the server doesn't safely reboot -- you get this.
So, we set things back to Local System and bam it worked. Swapped it to the domain user, no worky worky. Ok. Swapped it to Local System, rebooted, swapped it to domain user, rebooted, bam -- worky worky. All was good in our world. Later that morning it crapped out again... still working on that now but the priority is changing and I'm not sure we're going to continue work on this problem so I wanted to post something in case this happens to someone else.
What caused ours was we did an update and, apparently, we learned that it's bad practice to let Sql Server run as Local System so we changed it to a domain user. We never rebooted, but restart the service. A month later, we do updates. We don't reboot. A month goes by and a power strip fries causing the server to have an unexpected shutdown. Yet another month later we find out problem because we rarely connect to this particular database (Interestingly, Sql Server 2008 worked fine... it was only 2005). Or... at least this is the best we've come across.
Our admin guy doesn't like Vista and likes to blame everything on Vista (refuses to let us test Windows 7)... so he Googled "sspi vista" or something like (I know it had sspi and vista, but it might have had another one... in case you need to Google it was well) that and ran across an article that pretty explained our scenario after we had a meeting we all remember these pieces and placed this picture together.
In my case, the time synchronization issue in the Windows 2003 domain environment was actually the issue.
This was quite easy to overlook as the two had been on two different time zones, whilst showing the same times on their clocks; which in effect was about 1 hour apart.
So other than the time on their watches, check the time zones as well.
Here is the full error: SqlException: A transport-level error has occurred when receiving results from the server. (provider: Shared Memory Provider, error: 1 - I/O Error detected in read/write operation)
I've started seeing this message intermittently for a few of the unit tests in my application (there are over 1100 unit & system tests). I'm using the test runner in ReSharper 4.1.
One other thing: my development machine is a VMWare virtual machine.
I ran into this many moons ago. Bottom line is you are running out of available ports.
First make sure your calling application has connection pooling on.
If that does then check the number of available ports for the SQL Server.
What is happening is that if pooling is off then every call takes a port and it takes by default 4 minutes to have the port expire, and you are running out of ports.
If pooling is on then you need to profile all the ports of SQL Server and make sure you have enough and expand them if necessary.
When I came across this error, connection pooling was off and it caused this issue whenever a decent load was put on the website. We did not see it in development because the load was 2 or 3 people at max, but once the number grew over 10 we kept seeing this error. We turned pooling on, and it fixed it.
I ran into this many moons ago as well. However, not to discount #Longhorn213s explanation, but we had the exact opposite behavior. We received the error in development and testing, but not production where obviously the load was much greater. We ended up tolerating the issue in development as it was sporadic and didn't materially slow down progress. I think there could be several reasons for this error, but was never able to pin point the cause myself.
We've also run across this error and figured out that we were killing a SQL server connection from the database server. The client application is under the impression that the connection is still active and tries make use of that connection, but fails because it was terminated.
We saw this in our environment, and traced part of it down to the "NOLOCK" hint in our queries. We removed the NOLOCK hint and set our servers to use Snapshot Isolation mode, and the frequency of these errors was reduced quite a bit.
We have seen this error a few times and tried different resolutions with varying success. One common underlying theme has been that the system giving the error was running low on memory. This is especially true if the server that is hosting Sql Server is running ANY other non-OS process. By default SQL Server will grab any memory that it can, then if leaving little for other processes/drivers. This can cause erratic behavior and intermittent messages. It is good practice to configure your SQL Server for a maximum memory that leaves some headroom is there are other processes that might need it. Example: Visual Studio on a dev machine that is running a copy of SQL Server developers edition on the same machine.
Occasionally, on a ASP (classic) site users will get this error:
[DBNETLIB][ConnectionRead (recv()).]General network error.
Seems to be random and not connected to any particular page. The SQL server is separated from the web server and my guess is that every once and a while the "link" goes down between the two. Router/switch issue... or has someone else ran into this problem before?
Using the same setup as yours (ie separate web and database server), I've seen it from time to time and it has always been a connection problem between the servers - typically when the database server is being rebooted but sometimes when there's a comms problem somewhere in the system. I've not seen it triggered by any problems with the ASP code itself, which is why you're seeing it apparently at random and not connected to a particular page.
I'd seen this error many times. It could be caused by many things including network errors too :).
But one of the reason could be built-in feature of MS-SQL.
The feature detects DoS attacks -- in this case too many request from web server :).
But I have no idea how we fixed it :(.
SQL server configuration Manager
Disable TCP/IP , Enable Shared Memory & Named Pipes
Good Luck !
Not a solution exactly and not the same environment. However I get this error in a VBA/Excel program, and the problem is I have a hanging transaction which has not been submitted in SQL Server Management Studio (SSMS). After closing SSMS, everything works. So the lesson is a hanging transaction can block sprocs from proceeding (obvious fact, I know!). Hope this help someone here.
open command prompt - Run as administrator and type following command on the client side
netsh advfirewall set allprofiles state off
FWIW, I had this error from Excel, which would hang on an EXEC which worked fine within SSMS. I've seen queries with problems before, which were also OK within SSMS, due to 'parameter sniffing' and unsuitable cached query plans. Making a minor edit to the SP cured the problem, and it worked OK afterwards in its orginal form. I'd be interested to hear if anyone has encountered this scenario too. Try the good old OPTION (OPTIMIZE FOR UNKNOWN) :)