I had a very specific question asked of me related to the SQLIOSIM.exe, checksum validation logic.  It is pretty simple logic (on purpose) but effective so here are the basics. The key is that there are multiple memory locations used to hold the data and do the comparison.   1.     ...

I was looking at data from a customer, in a different time zone (UTC+1) from mine, this week involving SQL Server AlwaysOn (HADRON) and found that lining up the timestamps in the various logs was challenging.   Some times are local to the SQL Server instance, others UTC and yet other utilities...

I was sitting through SQL Server 2012 training, and Ajay Jagannathan was showing us Management Studio.  Eric Burgess had worked on this topic.  He started covering some neat things, that have apparently been there for a while, but I just never played around with it enough to see what all you...

  A lot of you are probably familiar with pssdiag tool released for SQL Server 7.0 and 2000 and sqldiag.exe utility shipped with SQL Server 2005, 2008 and 2008 R2. These are data collection diagnostics tools that allow collecting data such as profiler trace, perfmon and DMV information. For sqldiag...

I ran into an issue yesterday where the EventSequence column appears negative (or could be truncated and won't sort correctly) in the Profiler display. Here is an example of the display from a trace that I debugged. When I looked at the raw format I could see the storage for the EventSequence was 8 bytes...

The short answer is that it is not an error and the message should be a WARNING. I looked at the latest, internal code base it has already been changed to a WARNING. if (!DeviceIoControl (volume, IOCTL_DISK_GET_CACHE_INFORMATION, NULL, 0, &m_diskCacheInfo, sizeof (m_diskCacheInfo), &dwBytes,...

In the course of my job, I use ADPlus (a command-line tool that ships with Debugging Tools for Windows) to capture hang dumps on a regular basis.  For both low and high CPU scenarios, I generally need 2-3 hang dumps spaced out over about 10 minutes.  Historically, I have always given customers...

Often we run into situations where there is a need to add a trace flag or a startup parameter other than the default startup parameters that SQL Server uses. What you may notice sometimes is that even after adding these parameters/flags, the desired behavior from those parameters/flags does not occur...

Today I had an interesting question about the CTRL+C handler for the SQLIOSim console execution.    After some investigation I found that a design change request is in order as the CTRL+C handler has a few holes-  (I am working on that part). The CTRL+C handler does not prompt you...

I just completed a lengthy bit of research and thought I would share it with everyone.   There are several trace flags and registry keys outlined in this post.    !!! As always USE WITH APPROPRIATE CAUTION !!!   From: Robert Dorr Sent: Tuesday, November 17, 2009 3:23 PM...

Starting with SQL Server 2005 SP3 and SQL Server 2008 the RDTSC counter is not used for timing in SQL Server but you may still have occasion to use RDTSCTest.   From: Robert Dorr Sent: Thursday, June 04, 2009 4:14 PM Subject: RE: SQL Troubleshooting - RDTSC   In the registry the speed is stored...

I was attempting to establish the command shell proxy on my local machine and ran into a series of errors.   As I looked at them more I decided to file some work items with the SQL dev team to provide better context in the message text.   I hope this post will help provide some insight...

There is a bug with the message spelling (fasion instead of fashion) but that is not the focus of this post. When launching the SQL Server Configuration Manager you may receive this message if the WMI connections and queries do not complete within 30 seconds.   For the customer case I just...

You can place ORCA on a central computer and allow it to control the sequencing from multiple client computers running OSTRESS.    To accomplish this you must configure the firewall properly. Note: Be sure to install the same version of the RML utilities on all machines.   ...

Recently one of our blog readers reported that when they tried to change the SQL Server account password in SQL Server Configuration Manager they were getting "WMI Provider Error Access is denied [0x80070005]".  This was happening on two separate Windows Server 2008 machines that were...

We are often asked how to extend the filtering of RML (ReadTrace/OStress) or Profiler.  Filtering during trace production is the preferred method because it typically reduces the overall impact of the Trace on the SQL Server throughput.   For late filtering you can generally use the Profiler...

This is an extension to by previous post about SQLIOSim data integrity testing. http://blogs.msdn.com/psssql/archive/2008/03/05/how-it-works-sqliosim-checksums.aspx SQLIOSim (.exe/.com) is the predecessor to SQLIOStress.   SQLIOSim is SQL Server independent utility, generating both SQL Server and...

The following is from a lengthy conversation I had with Kevin Kline.  I believe he will be posting more details along with his "Understanding SQLIOSim Output - http://sqlblog.com/blogs/kevin_kline/archive/2007/06/28/understanding-sqliosim-output.aspx )   ********** Final Summary for file...

I ran across a teaser this week that makes for a interesting blog post.  SQL Server uses a common batch parser for the SQLCMD, OSQL, SSMS Query Window in Command mode and various other locations. The primary job of this parser is to identify GO delimited batches.  However, it can also identify...

A few questions have come up about the differences between the features you can install on SQL Server 2008 called Management Tools - Basic   and Management Tools - Complete. So I thought I'd blog about these to resolve any questions you might have. Related to this are questions I've received on...

The Page Audit User is one of the main execution paths for data integrity checking.   SQLIOSim runs test cycles and during each test cycle the [Audit User] section of the .INI configuration file is used.  These workers perform various page audit actives. After the cycle completes SQLIOSim...

I and Microsoft will always opt for restore of a backup when corruption of the database is encountered.   This is the only way to safely restore the database to a known state.   All other actions, such as dbcc repair, can remove data from the database and break referential integrity...

This post assumes you have properly enabled the xp_cmdshell feature using the Surface Area Configuration tool and you have used Management Studio | Server Properties | Security to establish a proxy for xp_cmdshell execution. Sample command:   master..xp_cmdshell 'whoami' SQL Authentication...

I don't want you to be surprised when you see more use of SQLBPA.   It was 18 months ago when the development team approached the support team asking us to help identify issues for SQLBPA.   Several of us, including myself helped identify and rank a list of rules for SQLBPA that target...

This blog post is to again inform you "NOT" to consider SQLIOSim as an I/O performance evaluation tool!   Every other month or so I get a rash of questions about using SQLIOSim to validate I/O performance and I have to repeat the same information. As I have stated in other posts and...