Search results matching tag 'Troubleshooting'

Learn More About SQL Server IO and Query Tuning in These Webcasts

KKline — Fri, 14 Dec 2012 18:50:00 GMT

I'm doing two new webcasts next week on Wednesday, December 19th, one in the morning and the other after lunch.

SSDs are a Game Changer for SQL Server Storage

No, session is not exclusively about SSDs. But this is my first session on IO and storage tuning that emphasizes SSDs over hard disks. As Bob Dylan said "Times, they are a'changin'". This session on Wednesday, December 19th at 11:30 AM EST, sponsored by Astute Networks, takes you through all of the basics of storage and IO tuning, regardless of the underlying storage technology. I'll show you how SQL Server handles storage structures, how to identify IO activity on Windows and SQL Server, and best practices for minimizing IO bottlenecks. Register now for: Storage IO Best Practices for SQL Server and a New Approach to Solving Application Performance Issues.

Write Better SQL Queries

The next webcast on Wednesday, December 19th at 2 PM EST, is with me, Aaron Bertrand (Twitter | Blog) and SQLCruise Impresario & Microsoft MVP Tim Ford (Twitter | Blog) as we take you through the query tuning process, discussing important DMVs to use during query tuning, as well as demonstrating several essential query tuning techniques that every SQL developer should know. Not only are we presenting an hour of top quality technical content, we’ll also be giving away some cool prizes, including the grand prize of a paid registration for the upcoming SQLCruise Miami, a $1,395 value! Register now for: SQL Server Query Tuning Best Practices, Hosted by Kevin Kline and Aaron Bertrand with special guest Tim Ford

I hope to see you at both of these sessions next week! Best regards,

-Kev

-Follow me on Twitter!

Recap - SQL Saturday 151 in Orlando

KKline — Tue, 02 Oct 2012 14:19:00 GMT

It's always a feel-good experience for me to return to SQL Saturday in Orlando, the place where SQL Saturdays were started by Andy Warren (Twitter | Blog). On this trip, I delivered a full-day, pre-conference seminar on Troubleshooting and Performance Tuning SQL Server. I also delivered a session on SQL Server Internals and Architecture to a totally packed house. For those of you who emailed me directly, here's the link for the special SQL Sentry offer.

I got to attend the extended events session by Jack Corbett (Twitter | Blog), middle in the photo above. Good stuff, Jack! Jack led the Orlando PASS Chapter for a few years and, although he relocated back up to New England, he enjoys getting back to Orlando when the opportunity presents itself.

I also got a chance to do a podcast with Rodney Landrum (Twitter | Blog), in the SQL Saturday chef's outfit on the right. Rodney, you should get your blog details up at the PASS SQL blogger page, btw. Rodney is also known as "the guy with the Red-Gate tatoo". Ask him why, when you meet him in person. I'll post the direct link to our podcast when I get it from Rodney. But in the meantime, be sure to check out his SQLBeat webcast. There are lots of great speakers and respected authorities to hear on his podcast.

As I mellow with age, I've found that I most enjoy connecting with friends and building relationships. The above picture shows me, Eddie Weurch (Twitter | Blog), and Pam Shaw (Twitter), head of the Tampa PASS Chapter. Pam, Eddie, and I were swapping some hilarious stories about our early years in snowy climates. Pam had the good fortune to be pulled, face first, through the snow by her mom during a trip to the school bus stop on the first big snow of the season. Mom, it seems, wanted to make sure she got to the bus stop safely, but instead fell down two steps from the front door of their home, sliding all the way to the bus stop firmly clutching Pam's hand. ROFL!

I got to spend some time with Ryan Adams (left) and Kendal Van Dyke (right), as well. There may have been some liquor involved. However, the highlight of my evening was definitely when Kendal yelled "FINALLY!" at the waitress bringing our plates out ten minutes after the appetizers were served. Kendal was actually paying no attention to the waitress or the plates and was instead yelling at the TV where the Florida State vs South Florida football game was playing. The waitress, on the other hand, was mortified. Hilarity ensued as he tried to explain that he was not the least bit cross with her. :^)

Ryan is going to be presenting at the upcoming spring 2013 SQLCruise event. You should definitely attend! Ryan Adams has lot more content here (Twitter | Blog). Kendal, by the way, is a standing member of the current PASS Board of Directors. He's written some excellent content and, just recently, moved to Upsearch consultancy where my friend Allen White (Twitter | Blog) works. Kendal Van Dyke has more content here (Twitter | Blog).

I hope you're planning to attend a SQL Saturday event soon. And not just the event, but also the after-event gatherings as well. You can almost always be sure that most of the speakers will be there. It's a great way to enlarge your professional network as well as to make real and lasting friendships!

Enjoy,

-Kev

-Follow me on Twitter

Two New Slide Decks. Plus, the Week in Colorado.

KKline — Mon, 20 Aug 2012 15:03:00 GMT

I had the honor of traveling the great state of Colorado last week, speaking at the PASS chapters in Boulder, Colorado Springs, and Denver. At all three events, we had a stellar attendance and, at least in Denver, broke all the records in recent memory both in terms of overall attendance and in first-timers. Denver, in fact, was standing room only and had nearly 30 first time attendees. Great news! I also want to give a special shout-out of thanks and appreciation to Chris Shaw (Twitter | Blog) whose hard work and tenacity ensured that all of Colorado got to see me speak. From left to right, Gabriel Villa (Twitter), me, Chris Shaw, and Rebecca Mitchell (Twitter). If it weren't for Chris, I wouldn't have been there. Thanks for putting in the time, amigo!

New Slide Decks!

During the 3-day jaunt, I presented two of my more popular sessions. These are updated slide decks, in case you want to download them here:

UG - End-to-End Troubleshooting

and

UG - Top 10 SQL Server Administration Mistakes

Be sure to check in the Slides area of the website, if you want to see the links for SpeakerRate, and in the case of several of my presentations, white papers, video recordings, etc. It's the People that Matter

A Blast from the SQLPASS Past!

I've always tried to maintain the relationships I built with the founding members of the PASS board of directors. After their time on the PASS board, almost all of them have moved on from SQL Server to other adventures. Pam Smith, the first president of the organization, is now a professor. Guy Brown, the second president, is now the director of IT at his same employer, rather than just SQL Server as when he was on the PASS board. A few, such as Kurt Windisch, a former VP of PASS, and my good friend Joe Webb (Twitter | Blog), are still active in the SQL Server space. One relationship that I've enjoyed over the years is with PASS' original Microsoft liaison and now a Denver-area software entrepreneur Steve Murchie (at right) running his own healthcare IT outfit. Steve has been a source of inspiration to me and also of great advice for all things startup-related. It was great to connect with Steve and catch up on his latest doings.

I also got to enjoy an evening out with the local attendees after the Denver user group meeting. It was great to hang out with folks there. I got to meet Kevin Cox (twitter), a member of Microsoft's incredibly talented SQLCAT group, and for whom I was a technical editor on a SQL Server v6.5 book back in the Neanderthal era. That shows just how old both Kevin and I actually are. Other cool folks that I got to meet included Steve Wake, Mike Fal, Marc Beacom, Jason Kassay, Jason Horner and my ol' buddy, Kelly the Greeley Geek.

On top of that, long-time SQL Server MVP and all-around awesome guy Steve Jones (Twitter | Blog) visited. I kept him out way too late that night which, to be honest, isn't usually my style. But the good conversation propelled us on past midnight.

The Good Folks at SQL Server Professional and Windows IT Professional Magazines

I've written for SQL Server Professional (formerly the artist known as "SQLMag") in some form or another starting from my first cover article for them way back in the mid 1990's. My Tool Time column has been going strong there since, oh, around 2006 iirc. For most of the time I've known the folks at SQLMag, they were located in Loveland, CO but they were able to move to some incredibly nice digs just up the road in Fort Collins. In all the many years, I've written for them, I'd never been to their offices - until now. It was great to visit and break bread with Megan (to my right), Blair (across), and Jaylee (across and to my right)!

I've always supported SQLMag and encourage you to subscribe. On top of the goodness already in the digital magazine, there are some neat developments coming down the pipeline with SQLMag which I think we'll all enjoy. Be sure to subscribe today! (You can click the badge on the left or simply go to http://www.sqlmag.com).

What's Next?

My current travel schedule is pinned up on this blog post HERE. However, I also know of a couple on-line appearances and probably a trip between the long gap between now and my next in-person appearance at the Orlando SQL Saturday at the end of September, where I'll also be teaching a pre-conference seminar (register HERE for the seminar).

SSWUG

The first on-line event to note is my a presentation by SSWUG of my Leadership Skills for IT Professionals video series, starting on August 24th. Sign up using the hyperlink (note that a video plays immediately upon loading the webpage, in case you want to be ready to pause or stop it). You can also buy a DVD set of the 14 hours of leadership training content.

24HOP - The 24 Hours of PASS Event

I'll also be speaking on the topic of influence in the next 24 Hours of PASS coming up on September 20th and 21st. Registration for the twenty-four hours of around the clock presentations is completely free and well worth your time. Check the schedule for the event and register! Even if you can only watch one or two sessions (or even zero sessions), be sure to register so that you'll automatically be notified when the sessions become available as streaming media.

Enjoy!

-Kev

-Follow me on Twitter, LinkedIn, and Facebook

High-Availability White Papers and Resources for SQL Server

KKline — Thu, 26 Jul 2012 15:00:00 GMT

In foreground, attendee makes dreaded "shoot myself" hand sign to the speaker.

I was just telling the good people of Charlotte about how they (and how YOU) need to read all things by Paul Randal (blog | twitter), except for all of his cheesy romance novels like Caress and Conquer written under the nom de plum of Connie Mason.

There's lots more good stuff from Paul, just not romantic.

This is a 'so-last-version' whitepaper describing five common high-availability and disaster-recovery architectures deployed by customers, along with a case study of each. Although the white paper is specific to SQL Server 2008 R2 and isn't updated for AlwaysOn features, it's still really, really good. It covers:

Failover Clustering for High Availability with Database Mirroring for Disaster Recovery
Database Mirroring for High Availability and Disaster Recovery
Geo-Clustering for High Availability and Disaster Recovery
Failover Clustering for High Availability Combined with SAN-Based Replication for Disaster Recovery
Peer-to-Peer Replication for High Availability and Disaster Recovery

You can get it from this link. Not everything is transferable to new AlwaysOn technologies, but then again AlwaysOn is an Enterprise Edition feature. So the database mirroring recommendation can be upsized, in many if not all cases, to SQL Server 2012, while the SAN and peer-to-peer recommendations continue to hold fast.

In addition, I encourage you to get up to speed on AlwaysOn. There are two great AlwaysOn FAQs that I recommend. The first is Microsoft’s official AlwaysOn FAQ at http://msdn.microsoft.com/en-us/sqlserver/gg508768.aspx. The second comes from my buddy and high-availability expert Allan Hirt (blog | twitter) at http://www.sqlha.com/2012/04/13/allans-alwayson-availability-groups-faq/.

To get started with AlwaysOn, check out http://msdn.microsoft.com/en-us/library/cc645581.aspx.

Enjoy,

-Kev

Analyzing the errorlog

TiborKaraszi — Thu, 05 Jul 2012 11:53:00 GMT

How often do you do this? Look over each message (type) in the errorlog file and determine whether this is something you want to act on. Sure, some (but not all) of you have some monitoring solution in place, but are you 100% confident that it really will notify for all messages that you might find interesting? That there isn't even one little message hiding in there that you would find valuable knowing about? Or how about messages that you typically don't are about, but knowing that you have a high frequency can be valuable information?

So, this boils down to actually reading the errorlog file. Some of you probably already have scripts and tool that makes this easier than just reading every simple message from top to bottom. I wanted to share how I do it, and this is why I wrote my Analyze SQL Server logs article. Check it out. And, feedback is always welcome!

New White Paper: SQL Server Extended Events and Notifications

KKline — Wed, 25 Apr 2012 13:13:00 GMT

SQL Server comes with a wide array of tools for monitoring your environment. There are logs and traces that provide information when errors occur, but these are often used passively to react to events that have already occurred. There's PerfMon, and Profiler, and loads of Dynamic Management Views to check. But where to look?

As database administrators (DBA), we need to monitor our environments proactively and create solutions as issues arise. In this white paper, we will look at a couple technologies – event notifications and extended events – that can help you achieve these goals. With these two features, we’ll look at the error log and deadlocks, and demonstrate how you can get relevant information delivered as it occurs. We’ll also look at ways that run-time errors can be captured and used to help reduce the amount of time required to investigate issues.

This white paper, written by SQL Server MVP Jason Strate (blog | twitter), is a free download but requires a registration. Download the Extended Events white paper here.

And, as always, I enjoy your feedback. Thanks!

-Kev

Follow me on Twitter!

SQL Server Performance Tuning and Optimization in Jacksonville, FL on April 27th

KKline — Mon, 23 Apr 2012 13:15:00 GMT

One last reminder - If you're interested in learning more about troubleshooting and optimizing SQL Server performance, please consider coming to the full-day seminar I'll be giving this Friday. Full details are here: http://sqlperftuning.eventbrite.com/. We'll be working some exercises, so bring your laptop with an instance of SQL Server 2008 (or later) running on it. It'll be fun!

I also encourage you to come on down to SQL Saturday 130 the following day - whether there's an official registration for you or not. (But don't tell 'em I said that). :^)

Come by the booth for a visit. I'll be hanging out most of the day and have some nice swag to give away.

Enjoy,

-Kev

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Everybody Needs a Test Harness

KKline — Mon, 31 Oct 2011 14:17:00 GMT

When you're developing new Transact-SQL code or modifying some existing code, do you just launch directly into programming?

I know that I did just that, for years. It wasn't until I was trying to performance tune some existing code that I realized I hadn't actually taken caching of data and execution plans into account. So all those modified stored procedures that I was so proud of might not actually be faster than the first generation of procedures because I hadn't checked to ensure that I was testing cached programs against uncached programs (and, by extension, the data used by those programs). That's easy enough to fix with a test harness. Test harness were originally an actual, physical harness used by engineers to clamp down parts of an electrical or mechanical device they were prototyping. Ours is no different. It locks down all of the assumptions about our code (like my early, false assumption that I didn't need to clear the caches) and adds a metric or two for good measure - literally - so we can better measure what's happening in that code.

Here's what my test harness looks like:

/* Transact-SQL test harness by Kevin Kline, http://KevinEKline.com, Twitter at kekline */

/* Flush dirty pages from the buffer to the database files. */

CHECKPOINT;

/* Flush the data cache and procedure cache, respectively. For DEV environments only! */

DBCC DROPCLEANBUFFERS;

DBCC FREEPROCCACHE;

/* Enable statistics tracking for IO and timings. Remember, SET commands remain enabled during a session until disabled. */

SET STATISTICS IO ON;

SET STATISTICS TIME ON;

-- Whatever SQL code you'd like to process goes below.

SELECT SalesOrderID

FROM Sales.SalesOrderHeader H

WHERE CustomerID = 344

GO

SET STATISTICS IO OFF;

SET STATISTICS TIME OFF;

/* Textual Execution Plans, if desired.

SET SHOWPLAN_TEXT ON;

SET SHOWPLAN_TEXT OFF;

*/

I also like to include the execution plans a lot of the time. You might wonder why I don't save the execution plans for the GUI in SSMS? Well, I'm a big advocate of scripting in general because I like to automate activities. By pulling the execution plans using scripts, I can use SQLCMD to schedule a large number of query executions during the evening and have the results ready for analysis when I come back into the office in the morning. Workin' smarter, not harder, Baby!

So how does this test harness work for you? Do you use other elements in yours? If so, share your experiences here!

Thanks,

-Kevin

-Follow me on Twitter

Troubleshooting Repeated Login Failures on SQL Server

KKline — Fri, 21 Oct 2011 13:05:00 GMT

I’d recently experienced a situation where I was getting repeated login failures to a SQL Server where I knew that I had the correct user name and password. Each time, I’d get error 18456 in response.

"Login failed for user '<user_name>'. (Microsoft SQL Server, Error: 18456)".

The challenge when troubleshooting this error message is that you may have a problem with SQL Server or you may have a problem with Active Directory or Kerberos, if you’re using one of those authentication technologies.

A False Trail

When times are good, and you’re able to make a connection, you can always query sys.dm_exec_connections, to see how you’re connecting, for example, using NTLM rather than Kerberos. But that doesn’t help us when we can’t connect to the server at all.

In other situations, your problem might be caused by duplicate SPMs in Active Directory. MVP Russell Fields documented a nice solution for ridding Active Directory of duplicate SPNs here. Microsoft Support also mentions some troubleshooting steps for authentication problems here. Ok, that helps. But it’s not my solution.

MVPs to the Rescue

Fortunately, my MVP buddies Edwin Sarmiento (blog | twitter) of Canada and Bitemo Erik Gergely (blog) of Hungaria had already discussed and solved the problem for me.

Something Erik pointed out, but hadn’t occurred to me at first, is that if you’re getting this SQL Server error message then you’ve actually reached the server and probably aren’t having a full disconnect error. The second thing that Erik pointed out is the importance of the state element of this error message. A lot of the time, you can simply ignore the state element of an error message. But not this time. As it turns out, state is the key to solving the problem. For example, a state of 18 indicates that the password must be changed.

Microsoft provides a pretty good description of the states of error 18456 here, but it leaves out a few things. (You’ll get more useful info if you read all of the comments too). But again, Erik comes to the rescue by providing a complete and concise list of error 18456 states here.

Microsoft Improves the Documentation

Even better for all troubleshooting situation involving state information, Microsoft has now added state descriptions for errors in Books Online, including error 18456. When you look in your SQL Server error log, you see the state of the error and be able to make an accurate deduction about the nature of the error!

Hope this helps,

-Kev

-Follow me on Twitter

-More content on my blog

Who owns your jobs?

TiborKaraszi — Thu, 06 Oct 2011 16:13:00 GMT

Yep, another Agent blog. The topic of job owner has been discussed here before, but this is a specific situation, which potentially is a ticking bomb. First a quick recap of how agent does things:

When a job is owned by somebody who is sysadmin, then no impersonation is performed.

T-SQL jobsteps will be executed as Agent's own Windows authenticated login.
Other jobsteps (which operates as the OS level) is done in Agent's service account's context.

Above is, assuming you didn't ask for impersonation for the jobstep (Run As).

Last week, at a SQL Server admin class, Andreas Jarbéus from Swedish Match asked about job owned by Windows account and what happens when that person leaves the company. I was about to say "no problem, if the job owner is sysadmin", but I felt there was a bit more to it. The scenario is:

The job owner is member of a Windows/AD group. Say you have a "SQL Server DBA" group in your AD.
This group is added as a login to your SQL Servers. The persons in that group do not have individual logins in SQL Server - only through this group.
This group is sysadmin. (I'm not saying that having jobs in general owned by sysadmins is a best practice. You can for instance have vendors installing some software and you don't want to make them sysadmin. In such a case, clearly we don't want the job to keep running if that person would disappear. So, I'm targeting jobs owned by sysadmin here, and I would bet you have bunch of those.)
Somebody in this group creates an Agent job.
The person in the group leaves the company and is removed from this Windows/AD group.

Above is a pretty common scenario. The thing now is that the job no longer works. And here's the reason:

If the owner was somebody in Windows/AD who's SID exists in SQL Server (the individual was added as a login to SQL Server), then the job will still work. This also applies for SQL Logins which might be disabled (like "sa" for instance). The reason for this is that the SID for the job owner exists in sys.server_principals and SQL Server will know that this SID is sysadmin. Since Agent won't do impersonation for sysadmins, there's no need to "go out to Windows" and see if this SID exists in Windows/AD. Remove the login, and the job will stop working, though - but you have at least don't something explicitly inside your SQL Server to cause this (removed the login).

But when the owner's SID don't exist in sysadmin we have a problem. The problem is that the recorded owner of the job is the SID for the Windows user, even though that SID doesn’t exist in sys.server_principals. As long as this still exists in Windows/AD, the job will work just fine. Agent will run this job owned by ?, ask Windows who this SID is and see that this SID is a member of a group which exists as a login in SQL Server and that is sysadmin. Now, imagine what happen if the SID doesn't exist in Windows anymore. The job is owned by ?, and that is all that SQL Server knows. The SID no longer exist in Windows/AD so you there's nobody to tell SQL Server "Yeah, this used to be a sysadmin in SQL Server - through a group membership in Windows/AD".

Even worse, the job seems to keep working until you re-start the SQL Server service, some caching going on. Makes it even more difficult to determine why the job suddenly stops working: "We deleted this Windows account 4.5 months ago." This is easy to repro, and you don't even need a domain (local Windows accounts and groups work just fine):

Create a Windows group for this.
Create a Windows account for this.
Add the Windows account to above group.
Add above group as a login to SQL Server.
Make this group sysadmin.
Create a job, with two jobsteps:
T-SQL which executes: PRINT ORIGINAL_LOGIN() + ' | ' + SUSER_SNAME() + ' | ' + USER_NAME()
CmdExec which executes: WHOAMI.EXE
(Above isn't really necessary, but useful for testing other impersonation aspects of Agent)
Specify the Windows account as owner of the job.
Run the job, make sure it works fine.
Remove the Windows account from the Windows group.
Run the job and see it fails.

I'm sure this has been blogged before, but I was a bit surprised by it. I have now added a check for this in my "Check best practices" stored procedure I run every day... On the flip side, this doesn't seem to happen for multi-server (MSX) jobs, the ownership seems to have special handling for these - you will see if you check the owner_sid in sysjobs.