Be Cautious When Critizing About Guidance

TSQL
I recently posted some comments about some guidance offered by Microsoft when talking about the CXPACKET wait type. Nothing I said was wrong, no. But, evidently there are a few whip smart and agile people who work for Microsoft. Specifically, Rick Byham, who works for the team tasked with taking care of the SQL Server Books Online. Why am I calling Mr. Byham smart and agile. Evidently he saw the blog post and has completely updated the description for CXPACKET at MSDN: Occurs with parallel query plans when trying to synchronize the query processor exchange iterator. If waiting is excessive and cannot be reduced by tuning the query (such as adding indexes), consider adjusting the cost threshold for parallelism or lowering the degree of parallelism. WHOOP! That's awesome work. Thanks Mr. Byham. Of…
Read More

SQL Server Log Backups

SQL Server 2008, SQLServerPedia Syndication, TSQL
While presenting a session on Common Backup Problems both at SQL Saturday in Orange County and at SQL Connections in Las Vegas, questions came up regarding whether, when, and how your databases should be configured in FULL recovery mode and what that means for your recovery plans. To boil the questions down to as simple a single statement as possible: Should your database be in FULL recovery mode at all times which requires you to run log backups on a regular schedule? The same question came up while Brad McGehee(blog|twitter) was presenting a session on using the settings on your SQL Server instance and your database to ensure you got proper performance. We both answered the question the same way, but our emphasis was slightly different. Brad’s answer was that,…
Read More

Small PowerShell Script

PowerShell, SQL Server 2008, SQLServerPedia Syndication
I'm still trying to learn PowerShell better. The opportunity to answer simple questions and problems with the tool is hard to pass up. We had a need to clean up data directories where data files were left behind or people put inappropiate files, so I wrote the following Powershell script: [sourcecode language="powershell"]param([string]$filelocation="",[string]$sqlinstance="(local)") Set-Location $filelocation foreach($file in get-childitem) {$base = $file.Name; $result = Invoke-Sqlcmd -ServerInstance $sqlinstance -Query "SELECT DB_NAME(mf.database_id) AS db FROM sys.master_files mf WHERE RIGHT(mf.physical_name,LEN('$Base')) = '$Base' UNION ALL SELECT 'NoDb' AS db WHERE NOT EXISTS (SELECT DB_NAME(mf.database_id) AS db FROM sys.master_files mf WHERE RIGHT(mf.physical_name,LEN('$Base')) = '$Base');" ; if($result.DB -eq "NoDb" -and $file.Extension -ne ".cer"){Remove-Item $base}} It's a very simple script. It takes a UNC and a server instance and then walks through the files in the UNC and validates…
Read More

More Free Training

SQL Server 2005, SQL Server 2008, TSQL
Quest Connect 2009, taking place in October 21 for 24 hours, looks like it's going to have 64 different sessions, live and recorded, by a variety of the names in the industry. It's another chance to dig in and learn the details on a variety of topics from some of the top names in the business. Can you say Tom LaRock? How about Tim Ford? I know you want to hear from Brent Ozar. Those are just some of the featured speakers. There are a whole slew of others, it's worth pursuing, and did I mention, the price is right. I recorded a session for them last night. It's on the basics of understanding execution plans.
Read More

More Spatial Headaches

spatial data, SQL Server 2008, SQLServerPedia Syndication, TSQL
I keep thinking I've got a handle on spatial data and I keep finding out I'm wrong. I rewrote the cursor that my co-worker used into a query that joined the list of test criteria onto our list of locations. I used an OUTER APPLY to more or less run a check for each of the test criteria since, except for the proximity to the locations, there's no actual relationship between the test criteria and the location data for me to join on. The query looked something like this: [crayon-5a6d452ede7aa779306405/] The cursor was taking almost a full minute to return just under 400 rows worth of data. This query took about 25 seconds. SCORE! Unfortunately when I looked at the execution plan, the optimizer was not able to recognize that…
Read More

Spatial Data

spatial data, SQL Server 2008, TSQL
I work for an insurance company. If you think that maybe, we might be interested in the physical location of the things we insure, you'd be right. Actually, we're an insurance company predicated on the idea that risk can be managed. That means that not only do we know where your factory is located. We know the wind zone, earthquake zone, flood zone, rain zone and temperature zone it's in. We send engineers out to the site to inspect it and recommend upgrades. We track the upgrades and the condition of your facility. With all that location specific information, just how important do you think it is that with SQL Server 2008 we're finally getting a spatial data type? Yeah, exactly. We're in the process of launching our first full implementation…
Read More

Reading to Learn

spatial data, SQL Server 2008, SQLServerPedia Syndication
I just finished chapter 1 of Alastair Aitchison'snew book on SQL Server spatial data, "Beginning Spatial with SQL Server 2008." If this is the beginners book... oh boy. The advanced book must be insane. Seriously though, Mr. Aitchison seems to have written a fantastic book. I'm going to tear through it as fast as I can because I've got two projects that are looking to start using spatial data and quite frankly, I'm a bit lost. There's a great discussiongoing on over at SSC as to the worth of technical books for DBA's. It's based on this editorialby Tony Davis. I'm surprised by the number of people who say they don't use books. It seems that a lot more people use blogs and articles and discussion groups to learn. Maybe…
Read More

Execution Plan Estimated Operator Cost

SQL Server 2008, SQLServerPedia Syndication
I've said it over and over again, the costs on operators in execution plans, even in actual execution plans are estimates.  You need to understand that when looking at your execution plans. It's vital because you need to be able to distinguish between the truly costly parts of a plan and the less costly parts of a plan. Don't believe me? Take a look at this picture and see if you can spot the discrepancy: Spot it yet? Add up the costs for the operators visible in the part of the plan... Yep 125%.  And there's more to the plan that I'm not showing. I think this one must total near 200%. The statistics are up to date and there's no consistency errors in the database. These estimates are just off sometimes.…
Read More

Missing Index Information and Query Stats

SQL Server 2005, SQL Server 2008, SQLServerPedia Syndication, TSQL
So the goal was to find a way to pull information from sys.dm_exec_query_stats so that we could identify poor performing procedures that were in cache at the moment and combine it with missing index information from sys.dm_db_missing_index_details. We're combining these because we're working with a Microsoft Dynamics CRM database that is almost all ad hoc queries and lots of them are against tables with missing indexes. The hope was to identify necessary indexes merely by looking at the longest running queries. Unfortunately there is no way to combine data from the missing indexes set of DMV's and all the execution DMV's that show query stats, execution plan, etc. None of the missing index tables has a plan handle or a plan hash column that would allow you to combine that…
Read More

SQL Server 2008 Management and Administration

SQL Server 2008
I just got a book in the mail from a friend, Todd Robinson, who was the technical editor. The name of the book is Microsoft SQL Server 2008 Management and Administration. The book was written by Ross Mistry and Hilary Cotter. I don't know Ross Mistry and I think I met Hilary Cotter once, although I know who he is. However, since Todd was involved, I'm pretty sure this is going to be a high-end, must read. I just started and the initial chapter's discussion on using Windows Server 2008 sparked a few questions for my local admin team. I'm looking forward to more. Thanks Todd.
Read More