Jonathan Kehayias is currently employed as a Principal Consultant and Trainer for SQLskills, one of the best-known and most respected SQL Server training and consulting companies in the world. Jonathan is a SQL Server MVP and one of the few Microsoft Certified Masters for SQL Server 2008, outside of Microsoft. Jonathan frequently blogs about SQL Server, presents sessions at PASS Summit, SQLBits, SQL Connections and local SQL Saturday events, and has remained a top answerer of questions on the MSDN SQL Server Database Engine forum since 2007.
Jonathan is a performance tuning expert for both SQL Server and hardware, and has architected complex systems as a developer, business analyst, and DBA. He also has extensive development (T-SQL, C#, and ASP.Net), hardware and virtualization design expertise, Windows expertise, Active Directory experience, and IIS administration experience.
Outside of SQL Server, Jonathan is also a Drill Sergeant in the US Army Reserves and is married with two young children. On most nights he can be found at the playground, in a swimming pool, or at the beach with his kids.
Jonathan can be found online as @SQLPoolBoy on Twitter, or through his blog (http://sqlskills.com/blogs/jonathan)
The Performance Analysis of Logs tool is a general tool for collecting and analysing log data. With the addition of a template, it becomes an effective way of analysing data from performance counters for SQL Server, in order to diagnose performance problems and capture baseline information.… Read more13 July 2012
One of the most obvious bottlenecks in the performance of tempdb is caused by PAGELATCH, in-memory latch contention on the allocation bitmap of each data file used. We can use one of the rules-of-thumb to choose what should be roughly the best number of files, but how then do you check to see whether you've got it right for your data and workload?… Read more10 May 2012
In this excerpt from his book Troubleshooting SQL Server: A Guide for the Accidental DBA, Jonathan Kehayias provides a guide to identifying the causes, reacting to, and ultimately preventing the dreaded deadlock.… Read more18 January 2012
One of the more popular counters used by DBAs to monitor the performance, the Buffer Cache Hit Ratio, is useless as a predictor of imminent performance problems. Worse, it can be misleading. Jonathan Kehayias demonstrates this convincingly with some simple tests. … Read more12 December 2011
There has been much debate over the need for the Lock Pages in Memory privilege, on 64-bit versions of SQL Server. Jonathan Kehayias presents a "warts and all" account of its history, the confusions surrounding its use, and why he believes it's still a good default configuration for 64-bit SQL Server instances, even when running Windows Server 2008 and Windows Server 2008R2.… Read more29 September 2011
Three SQL Server MVPs, and stalwarts of the SQLServerCentral and MSDN community forums, provide fascinating insight into the most common SQL Server problems, why they occur, and how they can be diagnosed using tools such as Performance Monitor, Dynamic Management Views and server-side tracing. The focus is on practical solutions for removing root causes of these problems, rather than "papering over the cracks".… Read more28 September 2011
When healing a sick SQL Server, you must forget the idea that there could ever be a simple correspondence between symptom and disease: The art of troubleshooting is much more the art of discovering, and assembling, the various pieces of the puzzle so that you have a complete understanding of what is going on inside of a server… Read more
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