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Saturday, February 25, 2012

Communications link failure #0

We are intermittently getting this error on our SQL server. The front end is
access and this happens every so often causing the users to have to exit out
of access and reconnect. I'm by no means a SQL expert, and our programmer
who manages this database isn't sure what it is either, he says it's like
the server is just "forgetting his password" and dumping the ODBC
connection...
Any ideas/help would be appreciated.
Thanks!
ScottHi
You don't give what version of MDAC or SQL Server that you are using!
http://www.aspfaq.com/show.asp?id=2160
http://msdn.microsoft.com/data/mdac/default.aspx
Searching Google for "Communications link failure" turns up quite a few
things, it seemed to be quite common with SQL Server 6.5!
You may want to check that you don't have connection pooling.
Try logging the ODBC commands (on the client) and using Profiler on the
server to pin point if there is one particular set of circumstances when it
occurs.
Check your SQL Server logs and Event logs (on client and server) to see if
there in any information or event that corresponds to the timing of your
disconnections.
Use the MDAC component check to show the version and if you have a
consistent installation.
HTH
John
"Scott McDonald" wrote:
> We are intermittently getting this error on our SQL server. The front end is
> access and this happens every so often causing the users to have to exit out
> of access and reconnect. I'm by no means a SQL expert, and our programmer
> who manages this database isn't sure what it is either, he says it's like
> the server is just "forgetting his password" and dumping the ODBC
> connection...
> Any ideas/help would be appreciated.
> Thanks!
> Scott
>
>|||it's SQL 2000 on Windows 2003 and using Access 2003 - sorry . MDAC is
newest, which I think is x.7 or something...
"John Bell" <JohnBell@.discussions.microsoft.com> wrote in message
news:2B4BF663-A19B-4E40-B44A-D9684B757E4B@.microsoft.com...
> Hi
> You don't give what version of MDAC or SQL Server that you are using!
> http://www.aspfaq.com/show.asp?id=2160
> http://msdn.microsoft.com/data/mdac/default.aspx
> Searching Google for "Communications link failure" turns up quite a few
> things, it seemed to be quite common with SQL Server 6.5!
> You may want to check that you don't have connection pooling.
> Try logging the ODBC commands (on the client) and using Profiler on the
> server to pin point if there is one particular set of circumstances when
> it
> occurs.
> Check your SQL Server logs and Event logs (on client and server) to see if
> there in any information or event that corresponds to the timing of your
> disconnections.
> Use the MDAC component check to show the version and if you have a
> consistent installation.
> HTH
> John
>
> "Scott McDonald" wrote:
>> We are intermittently getting this error on our SQL server. The front end
>> is
>> access and this happens every so often causing the users to have to exit
>> out
>> of access and reconnect. I'm by no means a SQL expert, and our programmer
>> who manages this database isn't sure what it is either, he says it's like
>> the server is just "forgetting his password" and dumping the ODBC
>> connection...
>> Any ideas/help would be appreciated.
>> Thanks!
>> Scott
>>|||Hi
You may also want to switch protocols and check out the network in
general for possible problems.
John
Scott McDonald wrote:
> it's SQL 2000 on Windows 2003 and using Access 2003 - sorry . MDAC is
> newest, which I think is x.7 or something...
>
> "John Bell" <JohnBell@.discussions.microsoft.com> wrote in message
> news:2B4BF663-A19B-4E40-B44A-D9684B757E4B@.microsoft.com...
> > Hi
> >
> > You don't give what version of MDAC or SQL Server that you are
using!
> > http://www.aspfaq.com/show.asp?id=2160
> > http://msdn.microsoft.com/data/mdac/default.aspx
> >
> > Searching Google for "Communications link failure" turns up quite a
few
> > things, it seemed to be quite common with SQL Server 6.5!
> >
> > You may want to check that you don't have connection pooling.
> >
> > Try logging the ODBC commands (on the client) and using Profiler on
the
> > server to pin point if there is one particular set of circumstances
when
> > it
> > occurs.
> >
> > Check your SQL Server logs and Event logs (on client and server) to
see if
> > there in any information or event that corresponds to the timing of
your
> > disconnections.
> >
> > Use the MDAC component check to show the version and if you have a
> > consistent installation.
> >
> > HTH
> >
> > John
> >
> >
> > "Scott McDonald" wrote:
> >
> >> We are intermittently getting this error on our SQL server. The
front end
> >> is
> >> access and this happens every so often causing the users to have
to exit
> >> out
> >> of access and reconnect. I'm by no means a SQL expert, and our
programmer
> >> who manages this database isn't sure what it is either, he says
it's like
> >> the server is just "forgetting his password" and dumping the ODBC
> >> connection...
> >>
> >> Any ideas/help would be appreciated.
> >>
> >> Thanks!
> >>
> >> Scott
> >>
> >>
> >>

Communication Link Failure?

Hai,

Iam using VC++ application to connect remote database(MSSQL) through network.

Everything works fine, if the network connection is active. If the network breaks and resumes, the application throws "Communication Link Failure" and do not get connected even after the network is resumed.

Client :

* Windows 2000 Professional

* MDAC 2.5

* VC++, using framework- CRecordset to access database

* PEER to PEER network configuration

* DSN through ODBC

Server :
* Windows 2000 Professional
* MDAC 2.8
* MSSQL Server
how to resume the database connection ?
Any one help me?
Thanks in advance,

If an existing connection fails due to broken network connectivity the client application must open a new connection to the server.

Does the new connection fail as well? If so, what is the full error message text?

|||

No..if the application is restarted the connection resumes..

Do i have to make a new connection after the broken network connectivity? Is there any other solution without reconnecting?

|||

Yes, you have to make a new connection after the broken network connectivity.

|||Thank you..

Communication link failure...

Hello,
We are the authors of an application written in PowerBuilder (type
Client-Server, database MSSQLServer2000).
After some time (1 hour) of client inactivity happens disconnect from server
and aplication reports error 'Communication link failure ...'

Please, would you help me, if exists some way how to set up an interval of
the connectivity between Client and Server. I wasnt able to find it out in
any help or manual.

Thank you very much in advance!
PavelOn Fri, 02 Apr 2004 16:31:41 +0200, Pavel Vetesnik wrote:

> Hello,
> We are the authors of an application written in PowerBuilder (type
> Client-Server, database MSSQLServer2000). After some time (1 hour) of
> client inactivity happens disconnect from server and aplication reports
> error 'Communication link failure ...'
> Please, would you help me, if exists some way how to set up an interval of
> the connectivity between Client and Server. I wasnt able to find it out
> in any help or manual.
> Thank you very much in advance!
> Pavel

You should add code to your application to capture the login dialogue
and log back on to the server in the event the server has dropped the
session and the SAME client session wishes to communicate with the server.

I suggest this because the timeout value used by the server could change
from release to release or be changed by the network/system administrators
if resource usage gets too high.

Communication link failure.

What could cause the Microsoft error listed below?
[Microsoft][ODBC SQL Server Driver]Communication link failure.
Thanks,Hi
Loosing connectivity to the server.
In what scenario does this occur?
Normally, network connectivity problems between a server and a client are
caused by faulty network cards, cables and switches. Also check that your
network drivers are up to date.
Regards
Mike
"Joe K." wrote:
> What could cause the Microsoft error listed below?
> [Microsoft][ODBC SQL Server Driver]Communication link failure.
> Thanks,

Communication link failure.

What could cause the Microsoft error listed below?
[Microsoft][ODBC SQL Server Driver]Communication link failure.
Thanks,
Hi
Loosing connectivity to the server.
In what scenario does this occur?
Normally, network connectivity problems between a server and a client are
caused by faulty network cards, cables and switches. Also check that your
network drivers are up to date.
Regards
Mike
"Joe K." wrote:

> What could cause the Microsoft error listed below?
> [Microsoft][ODBC SQL Server Driver]Communication link failure.
> Thanks,

Communication link failure.

What could cause the Microsoft error listed below?
[Microsoft][ODBC SQL Server Driver]Communication link failure.
Thanks,Hi
Loosing connectivity to the server.
In what scenario does this occur?
Normally, network connectivity problems between a server and a client are
caused by faulty network cards, cables and switches. Also check that your
network drivers are up to date.
Regards
Mike
"Joe K." wrote:

> What could cause the Microsoft error listed below?
> [Microsoft][ODBC SQL Server Driver]Communication link failure.
> Thanks,

Communication Link Failure Error

Hi,

I am using ADO in my application to connect and retrieve data from Microsoft SQL Server 2000 SP4. When I start my application, it establishes connection to the server successfully and I am able to retrieve data from the server. here is my test scenario:

1. unplug the network cable from the client machine and put the cable back in after some time. I disconnect from the database in my code when the client machine disconnects from the network

2. Once the client machine comes back on the network, I try to reconnect and retrieve data from the sql server but I get the following error message when I try to execute a sql command:

[Microsoft][ODBC SQL Server Driver]Communication Link failure

This problem occurs only with Window XP SP2. With XP SP1 it works fine. It seems to be problem on the client side as with Windows XP SP1 I do not get this error message at all.

Here are the various details:

1. The firewall is off on the client workstation.

2. the connection string is:

driver={SQL Server};server=AA;uid=BB;pwd=CC;database=DD

where AA = DNS name of server machine where sql server is running.

BB = user name

CC = password

DD= database name

3. The client is remote to the server.

4. I can ping the server machine when the client machine reconnects to the network.

5. I can still telnet the server when the client machine reconnects to the network.

6. client database provider is MDAC odbc.

7. the client and server machines are in the same domain.

8. Shared memory and TCPIP protocols are enabled and TCP is at the top of the list.

9. No alias is being used.

10. Viris scan is not installed.

11. force encriptioned is NOT checked.

Please reply.

It appears a connection pooling issue. The closed connections by the client app are returned to the pool and become invalid after you unplug the cable. Next time you try to connect, odbc reuse the invalid connectin and throw the error. Retry your connection or disable pooling should resolve your issue.|||

I am already doing this:

1. When the machine disconnects from the network, I close the database connection. when the machine reconnects to the network, I try to establish a new connection to the database.

2. The connection pooling is also disabled for SQL server odbc driver under Connection Pooling tab of ODBC Data Source Administrator.

Please reply.

|||

Good day,

Tahir posted this request in Oct this year, has there been any response yet?

We are experiencing exactely the same problem in completely different ODBC client and are desperately looking for a way around this.

regards

|||

I eventually managed to find a way around it. Here are the changes which I made to my code:

1. Changed the connection steing to use native OLE DB as follows:

Provider=sqloledb;Data Source=AAA;Initial Catalog=BBB;User Id=CCC;Password=DDD

where AAA = SQL Server name

BBB = database name

CCC = login user name

DDD= password

2. I declare a list which holds pending SQL request.

3. hook up ADO connection object's Connectioncomplete and Disconnection events.

4. when execution of a SQL query failes, an exception is raisedcatch this exception. check the list of pending requests. if it is empty then add this failed request into the list and disconnect from the database. (this will force to disconnect from an invalid connection if there is any). Do not attempt to disconnect from the database if there is already a pending request in the list.

5. I have a separate thread which attempts to connect to the database. once I have got connection to the database, i suspend that thread.

6. in disconnection event handler, I check if there is an error while I tried to disconnect from the database. If there is NO error then I resume the thread which attempts to connect to the database.

7. in connection event handler, I check if there is an error while I tried to connect to the database. If there is NO error then I start a timer which checks pending request list and if there is any pending request, send it to the SQL server and then empty the list.

Regards,

Tahir Sultan

|||

Tahir thanks for the response.

We still have a problem because we can only use ODBC?

regards

Amanda

|||

Can catch the error and retry the connection be one of your option?

Otherwise, please post your code here and we can try to repro it.

HTH

|||

At the moment we are diconneting and then re-connecting, but even this is not solving the problem. We need to stop the application to get rid of the error. This is only the case for the communication link failure error with all other errors diconnecting and re-connecting works fine.

regards

|||

I had the same problem when I was using ODBC. Even disconnecting and reconnecting did not work at all. I tried all possible ODBC driver configuration but none of them seemed to make any difference. But moving to native OLE DB driver solved the problem.

Tahir Sultan

|||We have a situation common to laptops. I'm convinced that it is the result of some power management setting (hibernate, hard drive shutdown, or standby), but can never log it to pinpoint it exactly. Any suggestions?

Communication Link Failure Error

Hi,

1. unplug the network cable from the client machine and put the cable back in after some time. I disconnect from the database in my code when the client machine disconnects from the network

2. Once the client machine comes back on the network, I try to reconnect and retrieve data from the sql server but I get the following error message when I try to execute a sql command:

[Microsoft][ODBC SQL Server Driver]Communication Link failure

This problem occurs only with Window XP SP2. With XP SP1 it works fine. It seems to be problem on the client side as with Windows XP SP1 I do not get this error message at all.

Here are the various details:

1. The firewall is off on the client workstation.

2. the connection string is:

driver={SQL Server};server=AA;uid=BB;pwd=CC;database=DD

where AA = DNS name of server machine where sql server is running.

BB = user name

CC = password

DD= database name

3. The client is remote to the server.

4. I can ping the server machine when the client machine reconnects to the network.

5. I can still telnet the server when the client machine reconnects to the network.

6. client database provider is MDAC odbc.

7. the client and server machines are in the same domain.

8. Shared memory and TCPIP protocols are enabled and TCP is at the top of the list.

9. No alias is being used.

10. Viris scan is not installed.

11. force encriptioned is NOT checked.

Please reply.

I am already doing this:

1. When the machine disconnects from the network, I close the database connection. when the machine reconnects to the network, I try to establish a new connection to the database.

2. The connection pooling is also disabled for SQL server odbc driver under Connection Pooling tab of ODBC Data Source Administrator.

Please reply.

|||

Good day,

Tahir posted this request in Oct this year, has there been any response yet?

We are experiencing exactely the same problem in completely different ODBC client and are desperately looking for a way around this.

regards

|||

I eventually managed to find a way around it. Here are the changes which I made to my code:

1. Changed the connection steing to use native OLE DB as follows:

Provider=sqloledb;Data Source=AAA;Initial Catalog=BBB;User Id=CCC;Password=DDD

where AAA = SQL Server name

BBB = database name

CCC = login user name

DDD= password

2. I declare a list which holds pending SQL request.

3. hook up ADO connection object's Connectioncomplete and Disconnection events.

5. I have a separate thread which attempts to connect to the database. once I have got connection to the database, i suspend that thread.

6. in disconnection event handler, I check if there is an error while I tried to disconnect from the database. If there is NO error then I resume the thread which attempts to connect to the database.

Regards,

Tahir Sultan

|||

Tahir thanks for the response.

We still have a problem because we can only use ODBC?

regards

Amanda

|||

Can catch the error and retry the connection be one of your option?

Otherwise, please post your code here and we can try to repro it.

HTH

|||

regards

|||

Tahir Sultan

Communication Link Failure Error

Hi,

1. unplug the network cable from the client machine and put the cable back in after some time. I disconnect from the database in my code when the client machine disconnects from the network

2. Once the client machine comes back on the network, I try to reconnect and retrieve data from the sql server but I get the following error message when I try to execute a sql command:

[Microsoft][ODBC SQL Server Driver]Communication Link failure

This problem occurs only with Window XP SP2. With XP SP1 it works fine. It seems to be problem on the client side as with Windows XP SP1 I do not get this error message at all.

Here are the various details:

1. The firewall is off on the client workstation.

2. the connection string is:

driver={SQL Server};server=AA;uid=BB;pwd=CC;database=DD

where AA = DNS name of server machine where sql server is running.

BB = user name

CC = password

DD= database name

3. The client is remote to the server.

4. I can ping the server machine when the client machine reconnects to the network.

5. I can still telnet the server when the client machine reconnects to the network.

6. client database provider is MDAC odbc.

7. the client and server machines are in the same domain.

8. Shared memory and TCPIP protocols are enabled and TCP is at the top of the list.

9. No alias is being used.

10. Viris scan is not installed.

11. force encriptioned is NOT checked.

Please reply.

I am already doing this:

1. When the machine disconnects from the network, I close the database connection. when the machine reconnects to the network, I try to establish a new connection to the database.

2. The connection pooling is also disabled for SQL server odbc driver under Connection Pooling tab of ODBC Data Source Administrator.

Please reply.

|||

Good day,

Tahir posted this request in Oct this year, has there been any response yet?

We are experiencing exactely the same problem in completely different ODBC client and are desperately looking for a way around this.

regards

|||

I eventually managed to find a way around it. Here are the changes which I made to my code:

1. Changed the connection steing to use native OLE DB as follows:

Provider=sqloledb;Data Source=AAA;Initial Catalog=BBB;User Id=CCC;Password=DDD

where AAA = SQL Server name

BBB = database name

CCC = login user name

DDD= password

2. I declare a list which holds pending SQL request.

3. hook up ADO connection object's Connectioncomplete and Disconnection events.

5. I have a separate thread which attempts to connect to the database. once I have got connection to the database, i suspend that thread.

6. in disconnection event handler, I check if there is an error while I tried to disconnect from the database. If there is NO error then I resume the thread which attempts to connect to the database.

Regards,

Tahir Sultan

|||

Tahir thanks for the response.

We still have a problem because we can only use ODBC?

regards

Amanda

|||

Can catch the error and retry the connection be one of your option?

Otherwise, please post your code here and we can try to repro it.

HTH

|||

regards

|||

Tahir Sultan

Communication Link Failure error

Hi Y'all,

When i alter 1 single value in my sql server 2000 sometimes i get following error:

1) [MICROSOFT][ODBC SQL SERVER DRIVER] Communication link failure

After clicking away:

2)CANNOT START MORE TRANSACTION ON THIS SESSION

Maybe someone can help me out on this?

Thanks!

Hi,

First, make sure that your largest column is the last column retuned. Make sure that you do not have any columns returned after a text or an image column

Second, have you recently finished any kind of an upgrade that may have impacted the MDAC? The default connection protocol in MDAC 2.5 was Named Pipes. In 2.7, it changed the default to TCP/IP. You mentioned that you are connecting via TCP/IP, but can you verify that in EM?

Third, you may try the following article which may be helpful to you.http://support.microsoft.com/kb/316872

Hope this helps. Thanks.

Communication Link Failure C++ & SQL Server

Hi Guys,

I am using C++ (Ver 6) that connects to a SQL Server 7 DB using ODBC drivers. The apps connects to the database in the start and listens to the users requests and replies with the required data.

The apps is working fine, but once in a while it looses connection and gives "Communication link failure" message.

I just restart the apps and it is able to reconnect and perform as normal without any problems.

I am not able to find the reason as this behaviour as its very much unpredictable!

The error is returned by SQLExecDirect() function.

The question is, since I still have the Connection Handle, is it possible to just reconnect to the database re-using the same handle ? or do I have any other choices ?

Thanks in advance.
Faisal.This is the wrong forum to ask this question. Try one of the SQL forums.|||You might get this error when the server gets restarted. I look for error 0x80004005 and reconnect to the server, it has worked well.

I'll move this thread to the SQL forum for a better answer.
|||

Hi Brian,

I think my question was confusing. I actually meant, how to re-connect to the DB using the same Connection Handle ? I am new to C/C++

Thanks.|||

Thanks for the help. As I mentioned above, I am new to C/C++ and dont know how to reuse the same connection handle. So that I dont need to re instantiate all the other classes that are using a reference to that connection handle

Hope you can help me out here.

Communication Link failure

Hello,
Sometimes my application accessing SQL Server via ODBC is giving an error message "Communication link failure".
The network and server looks fine, but I'am still getting it time to time.
Please recommend possible reasons and solutions.
Thanks indvance.We has some unnoticed unstable connections very difficult to find because NT retried to connect without warning (maybe just some lattency when you tried to access again a lan resource).
We checked with "ping -w5000 -t"
The problem was bad coupling male/female RJ45 connectors in some stations.

Hope this helps,
Csar.

Communication Link Failure

Why would we get a " Communication Link Failure "
I have seen " TimeOut Expired " and General Network Error and can
understand why we get those, but what about the one listed in subject
Any idea ?
Hi Hassan,
Did you ever find a solution to your problem? I had that same issue
today. I did some research and I found some FAQ that stating:
" Make sure that your largest column is the last column retuned. Make
sure that you do not have any columns returned after a text or an image
column"
I kind of don't fully understand it, but in my case.. I had some columns
will a NULL value at the end of the table. I moved them and it seemed
to fix my problem. Here's the site that I found:
http://www.15seconds.com/faq/ODBC/692.htm
Marc F.
Hassan wrote:
> Why would we get a " Communication Link Failure "
> I have seen " TimeOut Expired " and General Network Error and can
> understand why we get those, but what about the one listed in subject
> Any idea ?
>

Communication Link Failure

SQL 7, SP4
windows NT 4, SP6
SQL Server Agent jobs are failing, history
reports "ConnectionRead (SQLState 01000) Message 0
Communication Link Failure (SQL Sate 08S01) (Error 10004)
Jobs have been working fine until yesterday.
DBCC checkdb master, msdb, no errors reported.
I can backup the databases through a third party
application though, so what's up with the ODBC error
message reported by the job history?
Internet searching no help.
Need someone to come to my rescue!"Mary" <Mary_Scheffler@.urscorp.com> wrote in message
news:030e01c3fc16$dc082ff0$3a01280a@.phx.gbl...
> SQL 7, SP4
> windows NT 4, SP6
> SQL Server Agent jobs are failing, history
> reports "ConnectionRead (SQLState 01000) Message 0
> Communication Link Failure (SQL Sate 08S01) (Error 10004)
> Jobs have been working fine until yesterday.
> DBCC checkdb master, msdb, no errors reported.
> I can backup the databases through a third party
> application though, so what's up with the ODBC error
> message reported by the job history?
Check this out -- may be caused if there are pending transactions:
http://support.microsoft.com/defaul...kb;en-us;114630
Steve

Communication Link Failure

Thanks in advance for any help. I really appreciate it.
I am getting a strange error message when connecting to a single Sql Server
all of the sudden.
From enterprise manager the error is:
A connection could not be established to ServerName.
Reason: Communication link failure
Please verify Sql Server is running and check your Sql Server registration
properties (by right-clicking on the ServerName node) and try again.
From Query Analyzer the error is:
Unable to connect to server ServerName
ODBC: Msg 0, Level 16, State 1
[Microsoft][ODBC Sql Server Driver]Communication link failure
I am running Sql 2000 SP 3. Both my pc and the server are running Windows
2000.
If I use a different pc under the same login I am able to connect to the
server so the problem must be on my individual pc. I can also connect to
other Sql servers from the pc that is giving me problems. I have tried
uninstalling and reinstalling Sql and I get the same error message.
Does anyone have any idea as to the cause of this?Update...
I am able to register the server via IP address but not server name. When I
register by IP I get the same message that says:
SQL Server registration failed because of the connection failure displayed
below. Do you wish to Register anyway?
Communication link failure
If I click Yes I can then expand the server and view the databases as
normal. When I register by server name I get the same error message but I
still get the Communication link failure when expanding the server.
Help please!!!

Saturday, February 25, 2012

Communications link failure #0

Communications link failure #0

Communications link failure #0

Communications link failure #0

Communications link failure #0

Communications link failure #0

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Communication Link Failure Error

Communication Link Failure Error

Communication Link Failure error

Communication Link Failure C++ & SQL Server

Communication Link failure

Communication Link Failure

Communication Link Failure

Communication Link Failure

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