SQL SERVER – Database File Names and Extentions – Notes from the Field #025

[Notes from Pinal]: People believe Shakespeare’s birth date is on April 26. ” What is there in a name?” – I often hear this statement, which famously quotes from Shakespeare.  I think we developer believe in this statement as most of our various are either BAR or FOO. However, this is extremely inefficient and not convenient. There are many reasons we should have meaningful names to our objects, variables and various elements. There are times when incorrect naming convention can just get user in trouble or lead organizations to disaster. My friend Tim shares this humorous and interesting story. Read on

Linchpin People are database coaches and wellness experts for a data driven world. In this 25th episode of the Notes from the Fields series database expert Tim Radney (partner at Linchpin People) explains in a very simple words of names and extensions.


Database file naming standards are important. With Microsoft SQL Server the default naming standard is not a requirement so administrators can change from the default .mdf, .ldf and .ndf.  Recently I encountered a SQL Server instance that was having performance issues. The customer was reporting very slow response times and couldn’t figure out what the issue was.

Reluctantly the administrator reached out to the database team to get a professional opinion.  For the database team this was the first they learned of this new server so we quickly performed our standard check. Two things stood out which was high CPU utilization and the executable consuming the most CPU was antivirus as well as high disk IO.  We stopped the “on access” scan and performance of the SQL Server improved as well as disk IO dropped very low.

We reached out to our antivirus team and was assured that our standard policies were applied to this server which includes excludes for our standards for database file naming.  We continued to research deviations from our standard server build against this instance, since we did not build it and that is when we found the admin/vendor/customer (non dba) chose a different naming standard for the files.  The extensions they chose were.001 for data, .002 for logs, .003 for ndf.

Due to not having proper excludes for those files by the antivirus software, the customer created a denial of service attack against their self. The on access scan effectively created such a load that it prevented anything else from running.

This is not the first time I have encountered this type of issue and blogged about this in 2012. http://timradney.com/2012/06/18/file-extensions-for-sql-server-database-files/

If you decide that for whatever reason you would like to deviate from the default naming standard or your companies naming standard for database files, please get with the people that manage your antivirus software to make sure they create exclusions for your new naming standard.

If you want me to take a look at your server and its settings, or if your server is facing any issue we can Fix Your SQL Server.

Note: Tim has also written an excellent book on SQL Backup and Recovery, a must have for everyone.

Reference: Pinal Dave (http://blog.sqlauthority.com)

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SQL SERVER – Tools for Proactive DBAs – Central Management Server – Notes from the Field #024

[Note from Pinal]: This is a new episode of Notes from the Fields series. AlwaysOn is a very complex subject and not everyone knows many things about this. The matter of the fact is there is very little information available on this subject online and not everyone knows everything about this. This is why when a very common question related to AlwaysOn comes, people get confused.

In this episode of the Notes from the Field series database expert John Sterrett (Group Principal at Linchpin People) explains a very common issue DBAs and Developer faces in their career and is related to AlwaysOn Availability Group. Linchpin People are database coaches and wellness experts for a data driven world. Read the experience of John in his own words.


After completing several AlwaysOn Availability Group implementations there are two questions that come up frequently. When did my availability group failover? Where is my read-write replica? The answer to the first one is provided here [http://johnsterrett.com/2014/03/18/where-is-my-availability-group/ ]. Today, were going to look at the answer to the second question.

Where is my read-write replica?

The following script, when executed on an availability group replica returns the availability group name, current role state, and database name. This will let you know if this instance is hosting the PRIMARY “read/write” replica.

IF SERVERPROPERTY ('IsHadrEnabled') = 1 BEGIN
SELECT
AvailabilityGroup = ag.name,
AvailabilityGroupRole = ars.role_desc,
db.name
FROM sys.databases db
INNER JOIN sys.availability_databases_cluster adc ON db.group_database_id = adc.group_database_id
INNER JOIN sys.availability_groups ag ON adc.group_id = ag.group_id
INNER JOIN sys.dm_hadr_availability_replica_states ars ON ag.group_id = ars.group_id
AND db.replica_id = ars.replica_id
END
ELSE BEGIN
SELECT
NULL AS AvailabilityGroup, NULL AS AvailabilityGroupRole, name
FROM sys.databases
END

How do I check all replicas?

Now you know how to check if an instance of SQL Server participating in an AlwaysOn Availability Group is the “Read/Write” PRIMARY role. Next, we can utilize Central Management Server to run the same script across your other instances participating as replicas in your AlwaysOn Availability Group configuration. If you have never used Central Management Server this step-by-step guide can get you going in 10 minutes.

For this week, I have an windows failover cluster with two nodes “SQL2012DR” and “SQL2012PROD1 aka localhost,1433”). Each node hosts its own default instance of SQL Server. There are two separate AlwaysOn Availability Groups. Using Central Management Server, I can rerun the query above and quickly see where my read/write replica is.

Are your servers running at optimal speed or are you facing any SQL Server Performance Problems? If you want to get started with the help of experts read more over here: Fix Your SQL Server.

Reference: Pinal Dave (http://blog.sqlauthority.com)

SQL SERVER – Finding Last Backup Time for All Database – Last Full, Differential and Log Backup – Optimized

Four years ago, I wrote a blog post SQL SERVER – Finding Last Backup Time for All Database. It has been a very popular script. SQL Expert Sravani has posted a fantastic script which also displays last full, differential and log backup for the database – I have blogged about it here SQL SERVER – Finding Last Backup Time for All Database – Last Full, Differential and Log Backup.

Well, in technology, there is always space for improvement and we should always be ready to learn and progress. SQL Expert TheSQLGuru came up with further optimized script which also lists all the details which earlier blog post listed, and the script is very quick to execute. Here is the script.

SELECT d.name AS 'DATABASE_Name',
MAX(CASE WHEN bu.TYPE = 'D' THEN bu.LastBackupDate END) AS 'Full DB Backup Status',
MAX(CASE WHEN bu.TYPE = 'I' THEN bu.LastBackupDate END) AS 'Differential DB Backup Status',
MAX(CASE WHEN bu.TYPE = 'L' THEN bu.LastBackupDate END) AS 'Transaction DB Backup Status',
CASE d.recovery_model WHEN 1 THEN 'Full' WHEN 2 THEN 'Bulk Logged' WHEN 3 THEN 'Simple' END RecoveryModel
FROM MASTER.sys.databases d
LEFT OUTER JOIN (SELECT database_name, TYPE, MAX(backup_start_date) AS LastBackupDate
FROM msdb.dbo.backupset
GROUP BY database_name, TYPE) AS bu ON d.name = bu.database_name
GROUP BY d.Name, d.recovery_model

Thanks TheSQLGuru for excellent script, you win USD 20 Amazon Gift Card or INR 1000 Flipkart Gift Voucher. I have already sent you emails with details.

Reference: Pinal Dave (http://blog.SQLAuthority.com)

SQL SERVER – Finding Jobs Shrinking Database Files – Notes from the Field #023

[Notes from Pinal]: Search on the internet about ‘Shrinking Database’, you will find plenty of advice why it is bad and it should not be done. If you do not believe me, just try it yourself. Even I have blogged about it before that it is an absolutely bad thing to do. However, there are very few blogs which talks about how to solve this ancient problem. The reason, I call it ancient problem is that there are quite a few organizations which are doing this for many years and they have many different places where they have included Shrinking Database code. There are quite a few places, where I see that people have created database jobs to shrink the database. I was talking to Tim about this and he comes up with a beautifully simple script where he demonstrated how to find out jobs which are shrinking database files.

Linchpin People are database coaches and wellness experts for a data driven world. In this 16th episode of the Notes from the Fields series database expert Tim Radney (partner at Linchpin People) explains a very simple script to find out jobs shrinking database files.


Often when analyzing a SQL Server Instance I come across jobs that are automating shrinking a database file.  Checking for a shrinking operation is important when analyzing a server for a number of reasons.  One is that anytime a data file or log file has to grow, transactions have to wait until the growth operation is complete thus causing a performance impact.  Shrinking a log file can contribute to high virtual log file counts and shrinking a data file will lead to fragmenting the database.

I check to see if any database maintenance plans exist and if so I check to see if auto shrink has been chosen, occasionally I find this is the case.  I also have a TSQL script that will search for any reference to the word ‘shrink’ in a job step.  I find custom jobs like this more often than auto shrink being used in a maintenance plan.  Often times the justification for someone configuring a job like this is due to drive space issues.

In cases where the shrink is to reclaim drive space it is most often due to not having a proper backup routine in place for the transaction logs or a process that keeps a transaction open for an extended period of time.  The transaction log will need to be large enough to handle your index maintenance, ETL processes and transactions that occur between log backups.   If you find that you are having an erratic large growth, then you will need to examine what transactions or processes are holding open an active transaction for such a long duration or the frequency of your log backups.

Below is the script I use to search for the word shrink in any tsql job step.

DECLARE @search VARCHAR(100)
SET @Search = 'shrink'
SELECT  A.[job_id],
B.[name],
[step_id],
[step_name],
[command],
[database_name]
FROM    [msdb].[dbo].[sysjobsteps] A
JOIN [msdb].dbo.sysjobs B ON A.job_id = B.[job_id]
WHERE   command LIKE '%' + @Search + '%'
ORDER BY [database_name],
B.[name],
[step_id]

If you want me to take a look at your server and its settings, or if your server is facing any issue we can Fix Your SQL Server.

Note: Tim has also written an excellent book on SQL Backup and Recovery, a must have for everyone.


Related Articles:

Reference: Pinal Dave (http://blog.sqlauthority.com)

SQL SERVER – Finding Last Backup Time for All Database – Last Full, Differential and Log Backup

About four years ago, I wrote a blog post where I posted a script about finding backup time for all the databases. You can see the blog post over here SQL SERVER – Finding Last Backup Time for All Database. It has been a very popular script. However, this script was just giving details about last full backup time. SQL Expert Sravani has posted a fantastic script which also displays last full, differential and log backup for the database.

Here is the script.

SET NOCOUNT ON
GO
SET quoted_identifier OFF
DECLARE
@dbname AS VARCHAR(80)
DECLARE @msgdb AS VARCHAR(100)
DECLARE @dbbkpname AS VARCHAR(80)
DECLARE @dypart1 AS VARCHAR(2)
DECLARE @dypart2 AS VARCHAR(3)
DECLARE @dypart3 AS VARCHAR(4)
DECLARE @currentdate AS VARCHAR(10)
DECLARE @server_name AS VARCHAR(30)
SELECT @server_name = @@servername
SELECT @dypart1 = DATEPART(dd,GETDATE())
SELECT @dypart2 = DATENAME(mm,GETDATE())
SELECT @dypart3 = DATEPART(yy,GETDATE())
SELECT @currentdate= @dypart1 + @dypart2 + @dypart3
PRINT "#####################################################################"
PRINT "# SERVERNAME : "+ @server_name + " DATE : "+ @currentdate +"#"
PRINT "#####################################################################"
PRINT "DatabaseName Full Diff TranLog"
PRINT "##########################################################################################################################################"
SELECT SUBSTRING(s.name,1,50) AS 'DATABASE Name',
b.backup_start_date AS 'Full DB Backup Status',
c.backup_start_date AS 'Differential DB Backup Status',
d.backup_start_date AS 'Transaction Log Backup Status'
FROM MASTER..sysdatabases s
LEFT OUTER JOIN msdb..backupset b
ON s.name = b.database_name
AND b.backup_start_date =
(SELECT MAX(backup_start_date)AS 'Full DB Backup Status'
FROM msdb..backupset
WHERE database_name = b.database_name
AND TYPE = 'D') -- full database backups only, not log backups
LEFT OUTER JOIN msdb..backupset c
ON s.name = c.database_name
AND c.backup_start_date =
(SELECT MAX(backup_start_date)'Differential DB Backup Status'
FROM msdb..backupset
WHERE database_name = c.database_name
AND TYPE = 'I')
LEFT OUTER JOIN msdb..backupset d
ON s.name = d.database_name
AND d.backup_start_date =
(SELECT MAX(backup_start_date)'Transaction Log Backup Status'
FROM msdb..backupset
WHERE database_name = d.database_name
AND TYPE = 'L')
WHERE s.name <>'tempdb'
ORDER BY s.name

Sravani, please send me email at my mail id and I will send USD 20 worth Amazon Gift Card or INR 1000 Flipkart Gift Voucher for your wonderful contribution. If you use any such script in your daily routine. Please send me email and I will be glad to post the same on blog with due credit.

Reference: Pinal Dave (http://blog.SQLAuthority.com)

SQL SERVER – SSIS Data Flow Troubleshooting – Part1 – Notes from the Field #019

[Note from Pinal]: This is a new episode of Notes from the Field series. SQL Server Integration Service (SSIS) is one of the most key essential part of the entire Business Intelligence (BI) story. It is a platform for data integration and workflow applications. The tool may also be used to automate maintenance of SQL Server databases and updates to multidimensional cube data.

In this episode of the Notes from the Field series I asked SSIS Expert Andy Leonard a very crucial question – How to troubleshoot SSIS data flow? It is such a complicated problem that everyone thinks they know, but not everyone can resolve this issue. Any Leonard is a world renowned expert, explains in this blog post how to troubleshoot SSIS data flow.


SQL Server Integration Services (SSIS) is designed to move data. Several SSIS tasks can move data but the Data Flow Task is arguably used most to accomplish moving data. When bad things happen to good developers, it helps to know how to troubleshoot. Writing about all the ways to troubleshoot an SSIS Data Flow Task will take more than one post. So this is Part 1.

Building a Quick Demo Package

If you are interested in working through some demos with me, create a new SSIS project named DataFlowTests. Add a Data Flow Task to the Control Flow as shown in Figure 1:

You can use any source data you desire, but I am going to use a file containing weather data captured from my weather station here in Farmville, Virginia beginning in December 2008. You can obtain this data here. Click the Data Flow tab to edit the Data Flow Task. Add a Flat File Connection Manager configured to consume the sensor1-all.csv file containing the December 2008 weather data. Add a Flat File Source adapter and link it to the Flat File Connection Manager. You Data Flow should appear as shown in Figure 2:

To test the Flat File Source adapter, we need to connect an output to another component. Add a Union All transformation and connect the output of the Flat File Source to it, as shown in Figure 3:

You can now test-execute the SSIS package. You should see results similar to those shown in Figure 4:

This data flow isn’t doing very much. The Flat File Source adapter is coupled to the Flat File Connection Manager. The Flat File Connection Manager reads data from the sensor1.all.csv file you downloaded from andyweather.com. Weather data is read into the data flow from the file via the Flat File Connection Manager and the Flat File Source adapter. The 106 rows of weather data are then passed into the Data Flow Path connecting the Flat File Source adapter output to the first Union All Input (Union All Input 1).

Insert a Warning

Let’s create an issue that will raise a warning. Open the Flat File Connection Manager Editor, click on the Advanced page, select the Min T column, and change its DataType property to “four-byte signed integer [DT_I4] as shown in Figure 5:

When you close the Flat File Connection Manager Editor, a warning icon displays on the Flat File Source adapter. If you hover over the Flat File Source adapter with your mouse, a tooltip will display some of the warning text as shown in Figure 6:

You can see more of the Warning if you execute the package and the view the Progress (if the package is running the SSIS Debugger) or Execution Results tab (if the package has been executed in the Debugger and then the Debugger has been stopped), as shown in Figure 7:

The warning we injected by changing the DataType property of the Min T column in the Flat File Connection Manager does not cause an error. The warning stems from the fact that there is a difference between the data type of the Min T column flowing into the Flat File Source adapter from the Flat File Connection Manager and the data type of the Min T column flowing out of the Flat File Source adapter. You can correct this warning by opening the Flat File Source adapter and clicking the Columns page. When opening the Editor (or Advanced Editor) of the Flat File Source adapter, you will be prompted as shown in Figure 8:

Click the “Yes” button to synchronize the Min T column’s data type in the Flat File Source adapter’s output (the metadata of the “output column”) with the Min T column’s data type supplied from the Flat File Connection Manager (the metadata of the “external column”).

Insert an Error

One way to generate an error in our simple data flow task is to configure the Flat File Connection Manager to perform an impossible data type coercion. Every value in the Min HI column contains “—“. Let’s configure the Min HI column in the Flat File Connection Manager and the Flat File Source adapter as data type Integer.

First, open the Flat File Connection Manager Editor and change the Min HI DataType property to DT_I4 as shown in Figure 9:

When you click the “OK” button, we see the same warning displayed in Figure 6 – the external columns are out of synchronization with the data source columns. Right-click the Flat File Source adapter and click Show Advanced Editor as shown in Figure 10:

When you attempt to open the Advanced Editor, you will be prompted to fix the data type mismatch between the output columns and the external columns. Click the “No” button to proceed, as shown in Figure 11:

When the Advanced Editor for the Flat File Source adapter opens, click the Input and Output Properties tab. Expand the Flat File Source Output node, and then expand the Output Columns node. Click on the Min HI column and change the DataType property to “four-byte signed integer [DT_I4] as shown in Figure 12:

Click the “OK” button to close the Advanced Editor. Note the Union All now displays a validation error as shown in Figure 13:

What has happened? The tooltip reveals an issue with a metadata mismatch, but the error is truncated. We can view the full error message in the Error List by clicking ViewàError List as shown in Figure 14:

Note: The Error List option is missing from the View menu in some versions of SSDT-BI. In those environments, use the keystrokes. Hold down Ctrl and press \ followed by E.

The Error List window displays the full text of errors, warnings, and other informational messages, and is shown in Figure 15:

There are a couple ways to fix this error. The easy way is to delete the Union All and add a new Union All transformation in its place (the hard way is to edit the package’s XML).

Conclusion

We are going to stop here. We have introduced an error in the Flat File Source Adapter, though. And we will begin there in Part 2.

If you want to get started with SSIS with the help of experts, read more over at Fix Your SQL Server.

Reference: Pinal Dave (http://blog.sqlauthority.com)

SQL SERVER – Dude, Where is the SQL Agent Job History? – Notes from the Field #017

[Note from Pinal]: Everybody knows what is SQL Agent Jobs. We know that they run at regular interval and does the task assigned. However, there are way many more things we should know about SQL Jobs but do not know it or never learnt to care about it. One of the most essential elements of SQL Agent Job is history.

In this episode of the Notes from the Field series database expert John Sterrett (Group Principal at Linchpin People) discusses about SQL Agent Job History in this blog post. Linchpin People are database coaches and wellness experts for a data driven world. Read the experience of John in his own words.


In this tip of the week, I want to cover a common problem I see too often in the field. Multiple times I have been asked, “Dude, where is the SQL Agent Job History?” I had a job fail but I cannot view the history and get details towards why it failed. Today, I am going to cover why the job history is most likely disappearing on you.

Typically there are two reasons why your SQL Agent Job History is missing. First, someone or a process is running sp_purge_jobhistory to purge the history. Typically, I find that this isn’t the reason why your history is disappearing randomly.  Normally, it’s the default settings for the SQL Agent Job History that is purging your history. In this week’s tip were going to focus on the cause and effect of the default settings focusing on why you might need to change them.

Setup Demo

This tip is going to utilize two SQL Agent jobs that you need to download if you want to walk through step by step through the demo. The first job is “JobHistoryDemo – Divide by Zero” and the second is “JobHistoryDemo – Batch Process.” In this demo, were going to execute a job that will fail (Divide by Zero) and then were going to execute another job (Batch Process) over a 1,000 times.  For the purpose of this demo, the batch process job just does “SELECT 1” from tempdb.

For the purpose of this demo, were going to tweak the default setting for max rows per job. By default, this is set to 100. We are modifying this to be 1000 so we only need two jobs for the purpose of this demo. We will go into more detail about SQL Agent properties later in this tip.

USE [msdb]
GO
EXEC msdb.dbo.sp_set_sqlagent_properties @jobhistory_max_rows_per_job=1000
GO

Run Demo Code

After downloading and running the scripts you will have the two new “JobHistoryDemo” SQL Agent Jobs shown below.

Run the following script it will take about 30 minutes to complete. You will notice that it will start to automatically purge the history for all the SQL Agent jobs. We will dive into why during the next section of the tip.

/* Job fails */
EXEC sp_start_job @job_name = 'JobHistoryDemo - Divide by Zero';
DECLARE @i INT;
SET @i = 1200; -- default history retention for job history records
WHILE @i > 0 BEGIN
EXEC
sp_start_job @job_name ='JobHistoryDemo - Batch Process'
WAITFOR DELAY '00:00:02';
SET @i=@i-1
END

If you want to monitor the progress you can execute the following script. You will notice that the history gets purged once the “JobHistoryDemo – Divide by Zero” executes 1,000 times.

SELECT j.name, COUNT(*) Executions
FROM msdb.dbo.sysjobs j
INNER JOIN msdb.dbo.sysjobhistory h
ON j.job_id = h.job_id
GROUP BY j.name
ORDER BY Executions DESC

Here is a screen shot just right before we hit 1,000 executions.

Here is a screen shot just right after we had a 1,000 executions. Notice, that just 1,000 total SQL Agent job executions triggers the purging process. It doesn’t have to be limited to just a specific job.

Where did the history go?

Now we have the scenario described in the first paragraph of this tip. In this scenario, we have a controlled scenario where job history is missing. This can be very frustrating if you have multiple jobs executing frequently as it will seem like the data is being purged randomly.

Let’s take a look at the SQL Agent Job Activity monitor.   We can clearly see that the “JobHistoryDemo – Divide by Zero” job failed. Right click on the job and select view history.

You will notice all the job history is gone. Next we will show you most likely why you don’t see the job history.

How do we resolve the problem?

The first step to solving the problem is to identify the root cause. Reading along you might already know why the history is gone. Let’s drill down to the properties of the SQL Agent and focus on the history tab.

You will notice that the default setting is to only keep the last 1,000 history records for all the SQL Agent Jobs. The SQL Agent will also only keep 100 history records for a single job. It’s why we modified the Maximum job history rows per job property above for this demo.

Now that we have identified a root cause to this problem here is how you resolve it. Disable the limit size of job history log and utilize sp_purge_jobhistory to purge as needed to meet your storage and business requirements for maintaining agent job history.

Finally, if you need to maintain the results of SQL Agent jobs I recommend using the native functionality built-in to store message details. We will cover this in a future tip.

Are your servers running at optimal speed or are you facing any SQL Server Performance Problems? If you want to get started with the help of experts read more over here: Fix Your SQL Server.

Reference: Pinal Dave (http://blog.sqlauthority.com)