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Archive for the ‘Error Messages’ Category

Interesting Problem Today:

Ran into this issue a few times and every time its a variation of the same headache. So, here some ideas will be documented for posterity.

In general terms, the error looks like this:

Connecting to Subscriber ''
Agent message code 20084. The process could not connect to Subscriber ''
Microsoft SQL Server Native Client 11.0
SQL Server Network Interfaces: The target principal name is incorrect.
Cannot generate SSPI context

The error message seems nebulous and confusing — but for trained eyes it makes perfect sense. For me it took a while to make sense out of it.

There could be several things wrong under the hood, but essentially it says that the target SQL server that is is trying to connect to, does not have a valid SPN with Active Directory.

Meer from Microsoft has documented some information on troubleshooting this issue here. For more details, please read his article, as I’ll over simplify things and address a variation of the problem in this articles (which will be slightly different from his).

Example:

From SQLServerA, using UserA, if I’m trying to connect to SqlServerB, sometimes I get this error. Essentially, means SqlServerB does not have a valid SPN.

Resolution:

First, log into the machine that has SqlServerB. Open command prompt with Administrative privileges. Run the command below to see if there is a valid SPN.

 

SETSPN -L <SQL Server Instance Service Account>

 

If the output looks like the first image below, then the Sql Server instance does not have a valid SPN. Now its time to generate one.

Output without valid SPN:

Invalid SPN

Invalid SPN

Step 2: Download Kerberos Configuration Manager for SQL Server from here, and start generating one.

Step 3: Open Kerberos Configuration Manager for SQL Server from the same machine that has SqlServerB instance. When you run it, it shows something like this:

 

Kerberos Tool Output

Kerberos Tool Output

Notice that for Sql Server service, there is not valid SPN or misplaced SPN. So its time to generate one.

Step 4: Hit the “Fix it” button right next to it and generate one. Make sure the user account that is logged into the machine has domain controller permissions.

Step 5: Now run the same command as in Step 1, and the output looks different.

Output with valid SPN:

Valid SPN

Valid SPN

 

Voila !! Now you are able to connect to SqlServerB from SqlServerA using UserA

 

 

Hope this helps,
_Sqltimes

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Interesting one today:

Earlier in our lab environment, ran into this interesting error:

2019-06-20 00:18:46.67 Connecting to Distributor ''
2019-06-20 00:18:46.78 The replication agent had encountered an exception.
2019-06-20 00:18:46.78 Source: Replication
2019-06-20 00:18:46.78 Exception Type: 
Microsoft.SqlServer.Replication.ReplicationAgentException
2019-06-20 00:18:46.78 Exception Message: The snapshot could not be 
generated because the publisher is inactive.
2019-06-20 00:18:46.78 Message Code: 54057
2019-06-20 00:18:46.78

Replication from publisher to subscriber was set up correctly, but when the agent runs, the SQL Agent job stops with this error.

Resolution:

Go to Distributor and run this query to check the status of the publisher instance.


EXEC sp_helpdistpublisher

PublisherInvalid

As we can see, one of the publisher instance is set to Inactive. So now we need to reset it.

Run the script below to change the publisher status at distributor:


EXEC sp_changedistpublisher  @publisher = 'Publisher',  @property = 'active', @value = 'true'
GO

The result looks something like this:

Publisher_Active

Now  run the previous ‘sp_helpdistpublisher’ again and now the status is active:

PublisherValid

 

Hope this helps,
_Sqltimes

 

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Interesting error today:

When we query over linked server, we run into some restrictions. One such restrictions is this, where we could not query XML columns over LinkedServer connection.

For example, if the remote server table has a XML column in its structure, when we query the remote server for this table, we run this error:

--
-- Old query that throws this error
--
SELECT ID, XMLColumn
FROM LinkedServer01.DatabaseName.dbo.TableName
GO
Error : Msg 9514, Level 16, State 1, Line 1 
Xml data type is not supported in distributed queries. 
Remote object has xml column(s)

Resolution:

Not sure why this limitation exists, but there is a workaround: OPENQUERY

In the past, we’ve covered some key benefits of OPENQUERY and how it allows us to circumvent some limitations of remote-table-value function calls. Today, we’ll see another benefit of OPENQUERY in circumventing the XML limitation of linked servers.

Rather than querying XML directly, we convert XML into NVARCHAR(MAX) and revert it back to XML once the data is on local server.

--
-- Modified query to circumvent the limitation
--
SELECT ID, CONVERT(XML, XMLColumn) AS XMLcolumn
FROM OPENQUERY(LinkedServer01,
	'SELECT ID
		 , CONVERT(NVARCHAR(MAX), XMLColumn) AS XMLColumn
	FROM DatabaseName.dbo.TableName') AS RemoteQuery
GO

The XML data is retrieved as NVARCHAR(MAX) to the local machine; And immediately converted to XML before displaying.

 

Hope this helps,
_Sqltimes

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Quick one today:

Every time we we build a new cluster in our lab environment, we start with running cluster validation report before starting Sql Server installation. Once in a while, we need to go back to refer older validation reports.

All cluster validation reports are saved, by default, at the location below on the active node where the validation was executed from:

C:\Windows\Cluster\Reports

ValidationReport

 

Hope this helps,
_Sqltimes

 

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Interesting Error today:

While playing with XML DML, ran into this cryptic error.

Msg 2207, Level 16, State 1, Line 89
XQuery [dbo.Table.XMLColumn.modify()]: Only non-document nodes 
can be inserted. Found "xs:string ?".

 

While INSERTing a new XML element into an existing XML column, using the below code, this error pops up:

 

DECLARE @NewXMLElement VARCHAR(50) = 'Test'

UPDATE dbo.TableName
SET XMLColumn.modify('
		insert sql:variable("@NewXMLElement")
		into (/Parent/Child)[1]
	')
WHERE XMLColumn.exist('(/Parent/Child/NewXMLElement/text())') = 0
GO

Resolution:

Here, the goal is to INSERT a XML snippet into an existing XML column value. So, it is important that in the modify() function, the new XML element variable is defined as XML datatype

DECLARE @NewXMLElement XML = 'Test'

UPDATE dbo.TableName
SET XMLColumn.modify('
		insert sql:variable("@NewXMLElement")
		into (/Parent/Child)[1]
	')
WHERE XMLColumn.exist('(/Parent/Child/NewXMLElement/text())') = 0
GO

 

Hope this helps,
_Sqltimes

 

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Interesting one today:

In our lab environemnt, one of the SQL cluster environment ran into this error.

 

 

Error Message:

Clustered role 'Cluster Group' has exceeded its failover threshold.  
It has exhausted the configured number of failover attempts within 
the failover period of time allotted to it and will be left in a 
failed state.  
No additional attempts will be made to bring the role online or fail 
it over to another node in the cluster.  Please check the events 
associated with the failure.  After the issues causing the failure are 
resolved the role can be brought online manually or the cluster may 
attempt to bring it online again after the restart delay period.

The Cluster service failed to bring clustered role 'Cluster Group' 
completely online or offline. One or more resources may be in a 
failed state. This may impact the availability of the clustered role.

Resolution:

Errors like this are more common in Lab environments than in production environment. In any case, if you encounter the same error in production environment, then take extra caution before you follow these steps.

Possible Root Cause:

In lab sometimes, as part of some other effort, we inadvertently end up failing over the cluster several times within a short period of time. There is a setting in Cluster that measures the failover count.

  • If that count hits a particular threshold, it flags the Resource Group as ‘Failed’ state
  • And creates an entry in the the Cluster Events, that Cluster Resource Group failed after reaching the threshold (see the error message : Clustered role ‘Cluster Group’ has exceeded its failover threshold)

Resolution Steps:

According to this MSDN post, we could alter that failover count threshold to allow the resource group to come back up in a healthy state.

 

Step 1:

Go to Failover Cluster Manager >> Roles >> right click on the Resource Group and to go Properties:

  • Change the Maximum failures in a specified period to a larger number to account for the repeated failovers in recent hour.

ClusterFailoverThreshold_1

 

 

Step 2:

Go to Failover Cluster Manager >> Roles >>

In the bottom portion of the window where we the individual resources are listed, right click on the Resource that is in failed state and go Properties:

  • Increase the Maximum restarts in the specified period setting to a larger number to account for recent restarts.

 

ClusterFailoverThreshold_2

 

NOTE: This is not a standard solution for production environments.

Hope this helps,
_Sqltimes

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