Voice of the DBA

Category: Blog

Using the DAC with SSMS
I’m writing this post as a way to help motivate the #SQLNewBloggers out there. Read the bottom for a few notes on structuring a post.

While troubleshooting another issue, I needed to connect to SQL Server with the DAC. I couldn’t remember the syntax, so I looked it up quickly and ran into this link: Diagnostic Connection for Database Administrators. I added the ADMIN: to my connection in SSMS for a query window and clicked Connect.

This took entirely too long and then I got this:

That error resulted in a rabbit trail for me to debug this, but it worked out and I’ve learned a few things. The main one is to be sure that I’ve read the documentation and errors correctly.

As I tried a few things, including SQLCMD, I realized I had issues. I searched and found that the DAC gets set to a specific port. I checked the error log to get the number.

With that, I added it to my connection dialog, sure that this would work, but of course, it didn’t.

Eventually I stumbled on the post about errors and realized I should have checked the SQL Browser earlier. I thought about it, but discarded that thought because I could connect in other ways. Mistake. Check networking first, and networking is where the browser comes in. Sure enough, it was stopped.

The properties were set to DISABLED, so I had to change that before I could start it. I assume you can do that, if not, poke around the properties until you find that setting. With that changed, I started the service.

Then I could connect. Here’s the SQLCMD version.

With this working, the first command dialog at the top of this piece worked from an SSMS query window.

SQLNewBlogger

This was longer. What I thought was a quick lookup turned into a troubleshooting exercise that lasted about 20 minutes as I searched, read, experimented, etc. At least I made a bunch of screenshots as I was experimenting, so I had lots of data and didn’t duplicate anything.

The actual writing was only about 10 minutes, most of that looking through screenshots and trying to organize my thoughts.

References
- Enabling the DAC – http://www.mssqltips.com/sqlservertip/1801/enable-sql-server-2008-dedicated-administrator-connection/
- The DAC: Why, When, How – http://www.brentozar.com/archive/2011/08/dedicated-admin-connection-why-want-when-need-how-tell-whos-using/
- Errors when Trying to Use DAC Connection in SQL Server – http://www.sqldbpros.com/2013/10/error-when-trying-to-use-dac-connection-in-sql-server/
June 11, 2015
Unexpected Windows 10

This was strange. I noticed a new icon in the taskbar today. When I hovered over it, I saw this:

I downloaded the Windows 10 beta in a VM, but not here. However apparently some update added this. If I click on it, I see this:

I hadn’t been reading about Windows 10 too much. Mostly I want it for the copy/paste in the command line, but apparently I need to download it to get the upgrade. I hadn’t heard this before, and I was concerned.

If I click the reserve upgrade, I see this:

I don’t need a download now. Apparently I’ll get an automatic one when the OS goes to RTM, which is fine. I assume I can install it elsewhere, but perhaps I’m limited to this device?

It’s hard to tell. This will be an interesting process. I went through the FAQ and it appears I could upgrade later. The upgrade I reserved is for this device, so I’ll need to do this separately on my laptop.

A new process for Windows, and I’m interested to see how it works. I’ve seen a few MS people have issues with Windows 10 in demos, so I’m a little concerned about upgrading now, but I am looking forward to seeing the new OS in July or August.

June 10, 2015
T-SQL Tuesday #67 – Extended Events for DBCC

It’s the second Tuesday of the month and time for another T-SQL Tuesday. This time it’s #67 from Jes Borland on Extended Events. You can read the invite, and whether you can participate today or not, write your blog and leave a comment for Jes on her blog.

If you want to see all the topics from the past, I have them on a post here.

If you want to host, contact the founder of T-SQL Tuesday, Adam Machanic. He chooses the hosts and is always looking for people that want to participate. You just need a blog and a good idea.

Who Ran DBCC?

I ran across a question recently from someone that said DBCC messages had appeared in the error log, but no one had run DBCC. That’s not possible as DBCC isn’t run without someone, whether that’s a human or a service, executing the DBCC command.

In the past, I might recommend a trace to track this, but not I’d choose an Extended Events (XE) session. I’ll show how to set up a simple session, though be aware I’m not an XE guru. I’m sure there are better ways to structure this, but it worked well for me.

You can start quickly building a specific XE session by right clicking the Sessions folder under Extended Events in SSMS under Management. I tend to pick the wizard for getting started, though be sure to save the script later.

From here we get the opening screen for XE, which I won’t show. The next screen asks for a name for the session. It doesn’t matter, but once you start using XE, you’ll start to get quite a few session, so it’s handy to pick something that’s simple and easy to understand later.

I can choose to start the session here when I’m done, but don’t worry if you’re not sure. You’ll get a chance again later.

The next step is to decide whether you use a template or build a session from scratch. I’m not sure if any of these templates will work well as I haven’t dug in. In my case, I decided to just choose a generic session.

Now I need to pick the events. There are a lot, but I went down to get the sql_statement_completed as my event. This will let me see the text of a call, which is what I need.

A couple notes here. One, you might want to grow this screen so that you can read what’s in the lower windows. I know there’s a lot of data here, but this screen doesn’t seem well defined.

The second note is that don’t forget to add the event with the arrow button. Until you have an event (or multiple events) in the right window, you can’t click "Next".

The next step is to get the data fields you need. Again, there are a lot, and I limited this to what I needed. I grabbed the client host and app, as well as the database. Then I grabbed the service_principal_name and sql_text as well. This should let me determine who’s running the command.

I’ve got lots of data here, but I only care about the execution of dbcc checkdb. This means I need to filter things, which is my choice with the next screen.

Here I need to click in the top line to get a place to add a filter. Then I select sql_text from the drop down and choose like for the operator and "dbcc checkdb" for the value. This should grab events that execute with a dbcc call.

I have to choose where to store this data. Since this is mostly a check for me, I can just use the ring buffer and keep data in memory. I lowered this to 10 events, but you can certainly pick what works for you. If you care about auditing, drop this in a file. For a small session like this, there’s not much data that’s going to be captured.

I get a summary screen, which lets me review settings. I haven’t shown it here, but once I pass that, I get the "Success" screen. This is where I can start the session, and actually watch live data if I want.

For this, I’ll watch the live data.

I decided to test this first and see if it captures anything else. I ran a few queries, and then this:

Still a blank, live data screen. Then I ran checkdb. I saw the results, and then ran it a few more times.

As you can see, I now can see that I ran checkdb against the EncryptionPrimer database.

This lets me do some quick auditing of what’s happening with my DBCCs. A smart DBA might even use this to ensure that DBCC is being run against some databases, perhaps on a spare machine.

June 9, 2015
SQL Saturday #390 – Philadelphia Recap
I was at SQL Saturday #390 in Philadelphia last week and it was an exciting, but short time. The event was at the end of a five day trip for me, Seattle first and then Philadelphia, so I was tired by Saturday morning. However I enjoyed it, met lots of people, and learned a few interesting things.

Unit Testing with SQL Server and tSQLt

Friday I taught a pre-con event with Sebastian Meine on unit testing your T-SQL code with tSQLt. We had 9 people signed up, which was encouraging. Not a raging success, but certainly better than the 2 people that some friends had predicted. Everyone was interested in unit testing and producing better code.

The day went well, and we ended a touch early. There were some good comments and suggestions from people on unit testing techniques, including a solution to one of our exercises that I hadn’t expected. I learned a few places need the demos to be expanded a bit, but overall it felt like a good start to teaching unit testing. I’m looking forward to trying this at a few other events in the future.

Better Development at SQL Saturday

I was really only able to attend a few sessions (in addition to the one I taught) at SQL Saturday #390. However I was pleased to see that after my CI session, there was one on Continuous Delivery, and then one on Git for DBAs. Both of these topics are important, and well attended, which makes me think that more people are starting to lean towards building more engineered database development processes.

My CI session went well. I didn’t get to show the failing CI process based on a test and more data, but I did get lots of good questions that I need to answer in the next few weeks. A few of them (for me to remember).
- How do I get started with a small development team?
- How do I start adding tests in an existing software project?
- Can you demo a column rename (or table rename)?
- Show static data flowing through the process
It’s good to get questions, and I hope I answered them all. If I didn’t, or you need clarification, let me know.

Once I finished, I wandered over to see Mark Wojciechowicz talk about Continuous Delivery. Mark is a consultant that’s trying to keep a CD process working at a client’s site. He’s been working at it for awhile and we talked about it Friday (he was in my class) and Saturday. It sounds like he has some good things going, and using a home grown process that works well.

He showed some of the reasons why CD matters, especially for his client. They make lots of changes, and use a smooth process to push through bug fixes as well when there are issues with something in production. I hope he gets his deck up soon because he had some good quotes and notes in the PPT.

I especially like his thoughts that if something hurts in software, you should do it more. That comes from Thoughworks and some of the progressive companies that are rapidly building high quality software and don’t let the problems of deployment slow them down. They tackle those issues just like others, and you should, too.

From there I saw Justin Dearing talk about Git and DBAs. He’s a developer and tends to like the command line, but he showed how we can use Git for a VCS in the command line, but also from SSDT. That’s an interesting approach, and while I liked his message, I think some of the people there using a CVCS, like TFS, didn’t understand why Git matters. I need to write more on this as well.

Justin had a minor issue with branching, not because he doesn’t do it well or understand it, but because he’s moving fast and talking. That’s what I am, in general, against branching. The real world moves fast, it’s easy to get caught up with some other thoughts and get lost with branching. I need to formalize my thoughts as I’ll be talking branching at DevConnections (register and come see me in September).

Overall a good time and people seemed to really enjoy the SQL Saturday. I had about 20% of my attendees that were new, which is great. I hope to see more and more people coming to the events in the future.
June 8, 2015