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Interesting one today:

Earlier, when performing some cluster maintenance work, this error popped-up on the screen.

The specified disk or volume is managed by the Microsoft Failover cluster 
component. The disk must be in the cluster maintenance mode and the 
cluster resource status must be online to perform this operation

When attempting to format a new LUN to 64K allocation unit, this error popped up. Since the LUN/Drive is already added to the cluster, new format changes could not be made.

Resolution:

As the verbose error message suggests, assign this particular disk into “Maintenance Mode”, then perform formatting steps.

Go to Failover Cluster Manager and go to Storage > Disks; Identify the particular disk and right click and go to More Actions >> Turn On Maintenance Mode.

Cluster_LUN_Error

Once the disk is in maintenance mode, you’ll see under Status column as Online (Maintenance Mode).

Now we are free to format the disk. Computer Management >> Storage >> Disk Management go to the individual disk and right click and Format.

FormatClusterLUN

Now formatting works and once completed, go back to Failover Cluster Manager and set the disk back out of Maintenance Mode.

 

Hope this helps,
_Sqltimes
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Interesting one today:

XML DML is one powerful tool in Sql Server arsenal. In that value() function allows us to parse the XMl file and retrieve the values of attributes, elements, text, etc from the XML.

Using the sample XML below, we’ll explore various versions of using value() function.

Examples:

This is the sample XML file

XML_DML_Structure.PNG

DECLARE @X XML = '

....
'

SELECT @X.value('(/StoreConfigurations/ProcessingOptions/PasswordExpirationDays)<span id="mce_SELREST_start" style="overflow:hidden;line-height:0;">&#65279;</span>[1]', 'VARCHAR(2)') AS [Returns30]
	, @X.value('(/StoreConfigurations/ProcessingOptions/PasswordExpirationDays)[2]', 'VARCHAR(2)') AS [ReturnsNULL]

	, @X.value('(/StoreConfigurations/ReceiptTexts/ReceiptText/ReceiptHeaderLine1)[1]', 'VARCHAR(100)') AS [Returns YourStore]
	, @X.value('(/StoreConfigurations/ReceiptTexts/ReceiptText[@StoreNumber="6"]/ReceiptHeaderLine2)[1]', 'VARCHAR(100)') AS [Returns Your Street]

	, @X.value('(/StoreConfigurations/Hosts/Host/RetryCounter)[1]', 'VARCHAR(2)') AS [Returns 01]
	, @X.value('(/StoreConfigurations/Hosts/Host[2]/RetryCounter)[2]', 'VARCHAR(2)') AS [Returns 04]
	, @X.value('(/StoreConfigurations/Hosts/Host[3]/RetryCounter)[1]', 'VARCHAR(2)') AS [Returns 03]

	, @X.value('(/StoreConfigurations/Hosts/Host[@Prefix="X"]/RetryCounter)[1]', 'VARCHAR(2)') AS [Returns 01]
	, @X.value('(/StoreConfigurations/Hosts/Host[@Prefix="Y"]/RetryCounter)[2]', 'VARCHAR(2)') AS [Returns 04]
	, @X.value('(/StoreConfigurations/Hosts/Host[@Prefix="Z"]/RetryCounter)[1]', 'VARCHAR(2)') AS [Returns 03]

	, @X.value('(/StoreConfigurations/Hosts/Host[@Prefix="X"]/HostERCUse)[1]', 'VARCHAR(2)') AS [Returns X]
	, @X.value('(/StoreConfigurations/Hosts/Host[@Prefix="Y"]/HostERCUse)[1]', 'VARCHAR(2)') AS [Returns Y]
	, @X.value('(/StoreConfigurations/Hosts/Host[@Prefix="Z"]/HostERCUse)[1]', 'VARCHAR(2)') AS [Returns Z]

--/ReceiptHeaderLine1
IF (@X.value('(/StoreConfigurations/Hosts/Host[@Prefix="X"]/HostERCUse)[1]', 'VARCHAR(2)') = 'X')
	PRINT 'Yes, its X'
IF (@X.value('(/StoreConfigurations/Hosts/Host[@Prefix="Y"]/HostERCUse)[1]', 'VARCHAR(2)') = 'Y')
	PRINT 'Yes, its Y'
IF (@X.value('(/StoreConfigurations/Hosts/Host[@Prefix="Z"]/HostERCUse)[1]', 'VARCHAR(2)') = 'Z')
	PRINT 'Yes, its Z'
GO

Output:

The result looks like this:

XML_DML_Value

Also we could PRINT from the value function too:

XML_DML_Value_Print.PNG

Hope this helps,
_Sqltimes

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Quick one today:

Sequence is nice new feature in Sql Server, it allows a single location to manage IDENTITY-ies. In the past, we looked at one aspect of Sequence, today we’ll cover a bit more ground.

Once the Sequence definition is set, you may need to alter the definition. Below sample scripts show a way to modify some aspects of Sequence definition.

--
--   Create SEQUENCE and play with its DEFINITION
--
CREATE SEQUENCE SampleSequence
	AS BIGINT
	START WITH 0
	INCREMENT BY 1
	MINVALUE -10
    MAXVALUE 200
GO

SELECT name, start_value, maximum_value, current_value
FROM sys.sequences
WHERE name = 'SampleSequence' ;
GO

ALTER SEQUENCE SampleSequence RESTART WITH 2
GO

ALTER SEQUENCE SampleSequence MAXVALUE 300;
GO

SELECT name, start_value, maximum_value, current_value
FROM sys.sequences
WHERE name = 'SampleSequence' ;
GO

 

Hope this helps,
_Sqltimes

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Quick one today:

Frequently, we run into situations, where we need to put place holders, in a SQL script, that take different values based on some conditions or  settings. Essentially having variables about the script itself (and not the code)

We are taking about variables at the meta-level (script file level, and not the variables in the code itself)

SQLCMD mode within SSMS allows us to set placeholders / variables that will take new values (as you provide) right before executing the script.

First enable SQLCMD mode in SSMS:

SSMS_SQLCMD

In the query window, write some code as below:

--
--  Set variables in a script
--
:SETVAR DatabaseName "master"
:SETVAR TableName "MSreplication_options"

USE $(DatabaseName)
SELECT TOP 10 *
FROM syscolumns

USE $(DatabaseName)
SELECT *
FROM sys.objects
WHERE name LIKE '$(TableName)'
GO

SSMS_SQLCMD_Result

Observations:

Variable replacement occurs both in

USE $(DatabaseName)

and

WHERE name LIKE ‘$(TableName)

  • Having single quotes does not affect variable replacement, as this replacement occurs at the script file level (and node code level — if that makes sense).
  • Since this is a universal replacement capability, it allows you to use variable replacement anywhere in the code without need for special escape characters.
Hope this helps,
_Sqltimes

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Quick one today:

Sequence numbers is a valuable feature in Sql Server. Ir replaces the use of IDENTITY column property in some scenarios.

In the past we covered similar topic on how to query the current value of IDENTITY column. With SEQUENCEs it is slightly different:

--
--  Query SEQUENCE number details
--
SELECT name, start_value, maximum_value, current_value
FROM sys.sequences
WHERE name = 'TransactionIdSequence' ;
GO

 

Hope this helps,
_Sqltimes

 

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Quick one today:

Recently, we capture deadlock server side traces and needed a quick way to retrieve all SPIDs and procedures involved in deadlocks.

The deadlock trace graph is an XML file. If there was one or two deadlocks, we could amanyze it manually. But when you have several deadlocks (100’s or more) and need to analyze all the instances of deadlock entries in the trace, we need a query to parse the XML tree.

Enter XML DML!!

Sample Deadlock XML file looks like this:

We need to retrieve the procedure name involved in the deadlock. Use value() function to parse through the XML path and retrieve the attribute or element value.

Attribute value using @AttributeName

--
--	Return Attribute value in an XML element
--
SELECT	  CONVERT(XML, TextData).value('(/deadlock-list/deadlock/process-list/process/executionStack/frame/@procname)[1]', 'VARCHAR(100)')
		, CONVERT(XML, TextData).value('(/deadlock-list/deadlock/process-list/process/executionStack/frame/@procname)[2]', 'VARCHAR(100)')
		, CONVERT(XML, TextData).value('(/deadlock-list/deadlock/process-list/process/executionStack/frame/@procname)[3]', 'VARCHAR(100)')
		, CONVERT(XML, TextData).value('(/deadlock-list/deadlock/process-list/process/executionStack/frame/@procname)[4]', 'VARCHAR(100)')
		, CONVERT(XML, TextData)
FROM [After]
WHERE EventClass = 148

Pay attention the path mentioned — that shows what value to retrieve:

/deadlock-list/deadlock/process-list/process/executionStack/frame/@procname)[1]

  • ‘/deadlock-list/deadlock/process-list/process/executionStack/frame/’ is the location of the attribute
  • ‘@procname’ is the attribute to retrieve
  • [1] says to retrieve the vale from the first instance of such element — as XML could have multiple repeating similar elements. So we could also say [2], [3]… for respective instances.
  • We mention datatype VARCHAR(30) as a second parameter to value function indicating the type of value we are returning.

Attribute text:

Similarly, we could retrieve text value using XML value function:

--
--	Return XML element value
--
SELECT	  CONVERT(XML, TextData).value('(/deadlock-list/deadlock/process-list/process/executionStack/frame)[1]', 'VARCHAR(100)')
		, CONVERT(XML, TextData).value('(/deadlock-list/deadlock/process-list/process/executionStack/frame)[2]', 'VARCHAR(100)')
		, CONVERT(XML, TextData).value('(/deadlock-list/deadlock/process-list/process/executionStack/frame)[3]', 'VARCHAR(100)')
		, CONVERT(XML, TextData)
FROM [After]
WHERE EventClass = 148

Similarly, pay attention the path mentioned — that shows text to retrieve:

‘/deadlock-list/deadlock/process-list/process/executionStack/frame)[1]’

  • /deadlock-list/deadlock/process-list/process/executionStack/frame/ is the location of the text
  • [1] says to retrieve the vale from the first instance of such element — as XML could have multiple repeating similar elements. So we could also say [2], [3]… for respective instances.

For more information, please review MSDN article.

 

Hope this helps,
_Sqltimes

 

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Interesting one today:

We have a bunch of lab Sql Server boxes machines and sometimes after a fresh Sql Server install, when we try to open Activity Monitor, we run into this problem.

Error:

 

TITLE: Microsoft SQL Server Management Studio
 ------------------------------

The Activity Monitor is unable to execute queries against server DC2POLTPS02.
 Activity Monitor for this instance will be placed into a paused state.
 Use the context menu in the overview pane to resume the Activity Monitor.

Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED)) (mscorlib)

------------------------------

Since these are lab machines, we are remotely logged into the machines and looks like there is some setting that prevents Activity Monitor from opening successfully. Activity Monitor provides great detail on what is going on with Sql Server at any given point-in-time and such activity needs “high level insight” into the Operating System and Sql Server; Such “high level” permissions are not enabled by default for user accounts.

Following steps show a way to enable elevated permissions when logged in remotely.  From what I could gather from Microsoft Connect this seems like elevated permissions on remote operating system’s DCOM. So we need to enable Remote Launch & Remote Activation permissions on remote Operating System (lab machine)

Resolution:

RDP to the remote machine and

  1. Open Component Services (DCOMCNFG) from start menu
  2. In the left hand tree, under Console Root, expand Component Services, expand Computers, right-click on My Computer and go to Properties
  3. In My computer Properties window, go to COM Security tab.
  4. In the Launch and Activation Permissions section, click on Edit Limits button.
    1. In the Security Limits tab, see if your user/group name exists. If not add to the list by clicking on Add button.
    2. Once user is added, highlight the user and make sure it has both Remote Launch & Remote Activation permissions checked.
  5. In the Access Permissions section, click on Edit Limits button
    1. In the Security Limits tab, see if your user/group name exists. If not add to the list by clicking on Add button.
    2. Once user is added, highlight the user and make sure it has Remote Access permissions checked.
  6. Hit Okay to save changes.
  7. Now expand the My Computer in the left-hand tree and go to DCOM Config.
    1. Find Windows Management and Instrumentation and go to Properties.
    2. Go to Security tab and under Launch and Activation Permissions section, click on Edit button
    3. In the Security tab, see if your user/group name exists. If not add to the list by clicking on Add button.
    4. Once user is added, highlight the user and make sure it has both Remote Launch & Remote Activation permissions checked.
    5. (See the image below)
  8. Save all changes and re-open Activity Monitor
Activity Monitor Error

Activity Monitor Error

 

 

 

Hope this helps,
_Sqltimes

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