Wednesday, October 7, 2015

Speaking at SQL Saturday #445 - Raleigh, NC - October 10

I will be speaking this weekend at SQL Saturday #445 - Raleigh, NC. If you are in the area, please come out to this free training event to hear a bunch of great professionals talk about SQL Server. You can register for the event here: http://www.sqlsaturday.com/445/eventhome.aspx. So come on out and meet some great people who might be able to help you solve your worst problems.

I will be presenting two sessions on Policy Based Management and Performance Monitoring Tools.

Policy Based Management - Beyond the Basics
Policy Based Management is a great feature of SQL Server and easy to implement; however, for most organizations you need a way to customize it to your enterprise. Join me for this session as we take a deeper dive into PBM to see how you can customize polices, evaluate those polices across your entire enterprise environment, track those changes over time, and deliver reports to management showing your progress.

No Money for Performance Monitoring Tools? No Problem!
So you like the idea of using one of the commercially available performance monitoring tools but can’t convince your boss to spend the money? Then join me as we explore some absolutely free tools born right out of Microsoft’s customer support teams: DiagManager and SQLNexus. We will see just how easy it is to use them to collect and analyze performance data from your SQL Servers. These tools can get you started quickly without having to deal with the red tape.

Tuesday, July 21, 2015

PSSDiag Configuration Manager – A Companion for SQLNexus

Have you ever called Microsoft Customer Support for help with a SQL Server performance issue? The engineer will typically send you a self-extracting exe file with instructions to unzip the file on the server and run the pssdiag.cmd file to collect data while you reproduce your issue. Afterwards, you’re supposed to zip up the contents of the output folder and send it back to the engineer. How did the engineer compile that collection code so quickly? The answer is PSSDiag Configuration Manager, or simply DiagManager.

DiagManager is just a tool that you use to configure which performance items are to be collected by the SQLDIAG utility. The configuration files that come with SQLNexus (see my previous post) can be edited by hand, but sometimes it is much easier to use a GUI, and that’s where DiagManager can help you.

Version 12.0.0.1001 is the latest and to get it installed, just download it from codeplex and run SetupX86.msi. Go to the Start Menu and click on PSSDiag Configuration Manager to launch the program. Initially, you’ll get a warning screen to remind you the SQL client tools are required to run the collector. Just click OK to continue.


The first thing you’ll likely notice is a line of tabs across the top for different versions of SQL Server. Even though there are tabs for SQL Server 7.0 and 2000, they are no longer supported by this tool. If you really need a collection tool for those old version, then follow this link. But on the bright side, this latest version supports up to SQL Server 2014.

To get started using DiagManager, choose your version of SQL Server by selecting a tab.


Next, select the type of processor that your server has; for example, Intel or AMD. Itanium-based processors are no longer support for current versions of SQL Server. My server uses AMD processors, so I’ll need to click the AMD button.


Now you will need to enter the Machine name and the Instance name that will be monitored. The default values “.” and “*” will capture data for all SQL Server instances on the local machine. Typically for troubleshooting you won’t need to capture data for all instances. If your SQL Server installation is running on a Windows Failover Cluster, then you need to enter the SQL Server Virtual Name and not the physical host name. You’ll also need to specify the credentials used to connect to SQL Server. In my example, I’ll be monitoring a stand-alone instance named TRON\SQL2012 and connecting using Windows Authentication.


The section below that contains the Machine-wide Diagnostics are the counters you would normally see in Performance Monitor. All of the counters for SQL Server are checked by default as well as several for the Windows OS. At this point, you can add or remove counters that you want to capture. You can also specify the max file size (in MB) as well as the collection interval. The fault values are 256MB and 5 seconds.


Unchecking the Perfmon box will disable the collection of all perfmon counters.


The three check boxes above the perfmon box are for the Windows Event Logs. By default, DiagManager will only grab the event logs when SQLDIAG is shutdown; however, you can check the Startup box and it will grab them at both startup and shutdown. This is helpful if you need to do a before after comparison of the Windows Event logs. The collected data will be saved in the output folder as comma-separated (CSV) files. Unchecking the Event Logs box will disable the collection of the event logs.


In the top right half of the window, you will see Instance-specific Diagnostics; aka SQLDIAG and SQL trace. By default, SQLDIAG will only collect its data at shutdown, but you can check the Startup box to get before and after collections. This works the same as the event log collection. If you want to see the TSQL code that is used to generate this output, then just open the MSDiagProcs.sql file in Management Studio. Unchecking the SQLDIAG box will disable the collection of the SQLDIAG data.


Below SQLDIAG, you will see three tabs: Database Engine, Analysis Services, and XEvent. The Analysis Services tab is disabled for the public version of DiagManager, and in the current version, the XEvent tab should not be used to collect database engine data. This leaves the Database Engine tab, which is controls the events that will be captured using a SQL Trace. If you have ever used SQL Profiler to create a trace, then you should be very familiar with these options. Simply browse through the list to check or uncheck the items you need to collect.


Above the list of trace events, you will see a Trace checkbox and two dropdown lists. Unchecking the Trace box will disable the collection of any trace data. The “Max file size” dropdown just controls how large the trace files will get before they rollover. The default is 350MB. The Template dropdown list is a way to quickly check/uncheck events that will be collected. There are three templates included: General Performance, Details Performance, and PSSReplay. The PSSReplay is similar to the replay template within Profiler. General vs Details events is basically batch-level events vs statement-level events. The coolest thing about the trace templates, is that you can create your own. To do so, navigate to the TraceTemplates folder in the DiagManager install folder (C:\Program Files (x86)\Microsoft\Pssdiag\TraceTemplates). Open the folder that matches your SQL version, and make a copy of one of the XML files. Open that cop in your favorite XML editor and just change the “enabled” value to “true” for the events to collect and “false” for the events you do not want to collect, and then save the XML file.


The next time you open up DiagManager you should see your custom template in the dropdown list.


One big word of caution; a SQL Trace will cause the HEAVIEST overhead to your SQL Server, so be careful what items you choose to capture. If you are worried about adding too much overhead to your SQL Server, then consider using the “XEvent Batch_RPC Only” option in the Custom Diagnostics section. Checking this option will create an Extended Events session that will only capture “rpc_completed” and “sql_batch_completed” events. An Extended Events sessions adds far less overhead than a SQL Trace, but DO NOT enable both the SQL Trace box and the XEvent Batch_RPC option. Doing so would run both a trace and xevent session and add a lot of overhead to your SQL Server.

For the other items in the Custom Diagnostics section, you can select each one to see a description of what they do in the Instructions window. For example, the SQL 2012 Perf Stats script will gather data from DMVs about various items such as: top N queries, missing indexes, statistics, and even Availability Group info.

The Custom Diagnostics section is exactly as it sounds. You can create your own TSQL scripts or other types of custom collectors. Navigate to the CustomDiagnostics folder in the DiagManager install folder (C:\Program Files (x86)\Microsoft\Pssdiag\CustomDiagnostics), and create a new folder a new folder for your custom code. In my example, I created a folder called “SQL Database List” and added three files to the folder.


The first is just a TSQL script that has one command: “SELECT * FROM sys.databases;”. The DatabaseList.cmd is a Windows batch file that calls sqlcmd.exe and runs the DatabaseList.sql file.


The CustomDiag.XML file was copied from another custom folder and edited to reference the TSQL file and define whether it runs at startup or shutdown.


Once you have your custom collector created, close and open DiagManager and you should see your custom collector in the Custom Diagnostics list.


My example just captures a list of the databases, but you could easily create a script that captures data internal to one of your application databases.

Now that you have finally selected all the items that you want to collect, click the Save button at the top of the window. A Save Configuration window will pop up asking you what and where to save the collector files.


The Filename filed is where you want to save the PSSDiag.XML configuration file as well as all the collection scripts and tools. The option to create a CAB file is where DiagManager will compress and save all the files and scripts from the top folder. The CAB file is just a compressed (ZIP) file, and makes it easier to copy your collection tools to a remote server where the CAB file can then be uncompressed.

The last option available in DiagManager is the ability to compare PSSDiag.XML files. Just click the “Compare Config Files” button at the top of the window.


In the popup window, just select the two XML files that you want to compare, click the Compare button, and the output will be shown below.


Once you have created your collection set and/or the CAB file. All you need to do is copy the CAB file to the server to be monitored and execute the pssdiag.cmd batch file.


It will open a command prompt window and kick off each of the collection items you specified. Once you see the message “SQLDIAG Collection started” in green-colored font, then you can go recreate your performance issue.


Once you are ready to stop the collection, just press Ctrl+C. All of the data collected will be placed in the output folder, including any custom scripts that you may have created. That output folder can then be copied back to your workstation and fed into SQL Nexus for analysis. See my previous post for a detailed tutorial.

DiagManager definitely has a lot of configuration options to choose from, so learning which ones to use might take time. A good way to get started it is turn off all options except for one, and then run the data capture. Then you can look at the results in the output folder to really understand what that option does.

DiagManager, as well as SQLNexus, was created by the support teams at Microsoft, and they have made both of them freely available to the public to help in troubleshooting issues, so there’s no excuse not to try them out. I hope this tutorial will help you get started.

Tuesday, July 7, 2015

Use Trace Flag 902 to Recover from a Cumulative Update Failure

Recently, I ran into a critical error while I was helping a customer troubleshoot an issue in SQL Server. That may not sound like a big deal, but we were installing Cumulative Update 6 for SQL Server 2012 SP2 to fix our initial problem when we encountered the following error.


What gives SQL Server? We just upgraded several other instances on this same server. Why does this one have to fail right now? Well, a quick peak in the errorlog sure points me in the right direction.

Starting execution of SSIS_HOTFIX_INSTALL.SQL
:
:
Error: 9002, Severity: 17, State: 4.
The transaction log for database 'SSISDB' is full due to 'ACTIVE_TRANSACTION'.

Error: 912, Severity: 21, State: 2.
Script level upgrade for database 'master' failed because upgrade step 'SSIS_hotfix_install.sql' encountered error 3602, state 251, severity 25. This is a serious error condition which might interfere with regular operation and the database will be taken offline. If the error happened during upgrade of the 'master' database, it will prevent the entire SQL Server instance from starting. Examine the previous errorlog entries for errors, take the appropriate corrective actions and re-start the database so that the script upgrade steps run to completion.

Error: 3417, Severity: 21, State: 3.
Cannot recover the master database. SQL Server is unable to run. Restore master from a full backup, repair it, or rebuild it. For more information about how to rebuild the master database, see SQL Server Books Online.

SQL Server shutdown has been initiated.

This is definitely not good. Here we are trying to apply CU6 to fix one problem, and it we get another one in return. Needless to say, the CU6 upgrade failed, and SQL Server was dead in the water. Restarting the SQL Server service will just continue to run the internal upgrade and return the same error message.

It’s easy to see the root cause of the problem; the transaction log for the SSISDB database is full. But if we can’t start the service how will we ever get the error fixed? Lucky for us, Microsoft has a trace flag for that. Trace Flag 902 will bypass the internal upgrade script on startup. Just open SQL Server Configuration Manager and add -T902 to the Startup Parameters, save the changes, and then start the service.


SQL Server started up just fine and fully recovered all databases; including SSISDB. However, there was a warning about 1 transaction being rolled back for SSISDB.

1 transactions rolled back in database 'SSISDB' (5:0). This is an informational message only. No user action is required.

This is most likely from the SSIS_HOTFIX_INSTALL.SQL script that failed during the upgrade. Next, we need to check the configuration and the file sizes of the SSISDB database. Sure enough, the log file is still at its original size of 1MB with autogrowth was disabled.


For now, we can enable autogrowth for the log file and then save the changes. Next, we'll need remove the T902 trace flag from the Startup Parameters, and then restart the SQL Server service. Finally, SQL Server was able to startup without any errors. In the errorlog we can see the internal upgrade script ran successfully.

Starting execution of SSIS_HOTFIX_INSTALL.SQL
Start applying SSIS_HOTFIX_INSTALL changes.
:
:
Schema build in SSISDB has been updated to 11.0.5592.0
Execution of SSIS_HOTFIX_INSTALL.SQL completed

At this point, we need to rerun the CU6 setup again, so it can verify everything was correctly installed.


It shows the current patch level at 11.2.5592.0, which is correct, but the status is “Incompletely installed”. Just click next to continue with the upgrade to clear out the previous install failures.


So what is the lesson learned from this error? Should we leave autogrowth enabled on all databases before running a patch? Not necessarily, but it is an option. I think a better option is to keep a mental note of Trace Flag 902. With that trace flag, we were able to get SQL Server online long enough to correct the root problem, and we didn’t have to worry about changing any settings on a database.

References:


Tuesday, June 23, 2015

Exams 70-457 & 70-458 - Transition Your MCTS on SQL Server 2008 to MCSA: SQL Server 2012

This past week I finally completed the 70-458 exam to upgrade my certification to MSCA: SQL Server 2012. I never thought it would take me over a year to pass two upgrade exams, but sometimes life just gets in the way. I will say this is probably the hardest SQL Server exam I've taken so far.

The format of the upgrade exam is to combine questions from the three standard MCSA SQL Server 2012 exams, 70-461, 70-462, and 70-463. My hardest problem was dealing with the data warehouse questions; mainly the ones around Data Quality Services, Master Data Services, and especially the Project Deployment Model. I had never touched DQS or MDS before studying for this exam, and I can guarantee you that I would not have passed it without studying those topics. I found both to be very interesting features, but I have yet to come across a client that is using them.

The Project Deployment Model is a new concept for SSIS, and I really love it. I have worked with SSIS ever since it was introduced in SQL Server 2005, and this is a major improvement over the previous versions. Gone are the days when you had to design your own configurations for different environments or database connection strings. Everything is built into the SSIS catalog. The new features are awesome, but again, I had to really, really study the new deployment model and how to create packages that use environment variables.

All in all, I think it was a good test of SQL skills. Now let's see if I can pass the 70-459 before the end of the year.

Tuesday, April 28, 2015

Use PsPing When Working in Azure IaaS

Recently I’ve been learning more about how Azure functions and how it can help my customers. One of the best ways for me to learn about Azure was to build out my own environment using VMs, or Infrastructure as a Service (IaaS). All of that was easy; however, once the VMs were built I soon learned that Azure functions differently than an On-Premise solution.

The most basic network connectivity test that administrator use is the PING command. It is part of the ICMP protocol, but it’s disabled by default on each VM that I deployed. While it was easy enough just to configure the Windows Firewall to allow that traffic through, I decided to search for an alternative.

I found PsPing from SysInternals. It performs the same functionality as PING, but it uses the TCP protocol instead. When working in Azure, it can give you the same functionality without having to reconfigure your VMs.

For example, when I setup a SQL Server instance on one VM, I had difficulty establishing a connection to it from another VM. The standard PING proved to be useless, but PsPing proved its worth. By specifying the server name and a port number, I was able to successfully connect directly to the port number that SQL Server was listening on.


Immediately, I could see the benefit of using this new tool for more than just testing SQL Server connectivity. I can use it to specify any port number for any service. For example, I could ping port 80 if I’m testing a website, port 21 if it were an FTP server, or port 23 for telnet.

As I dig deeper into Azure, I’m sure I will discover many other new utilities that I can add to my own toolbox.

You can download PsPing from here.