Tag Archives for " Jeff Schwartz "

SQL Server 2012/2014 Extended Events for Developers – Part 1

By Jeffry Schwartz | Expert , Performance Tuning , SQL Development , SQL Server

— By Jeffry Schwartz Microsoft introduced Extended Events, a.k.a. XEvents, in SQL Server 2008 to aid in the analysis of performance problems. Both the capabilities and syntax were changed significantly on SQL Server 2012, and new (and very important) features were added in SQL Server 2014. Therefore, the focus of this document will be on […]

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Disk Metrics – Why PerfMon’s, SQL Server’s Filestats, and Disk Vendors’ Values Sometimes Appear to Disagree

By Jeffry Schwartz | Expert , Performance Tuning , SQL Server , Windows

— By Jeffry Schwartz Whenever multiple data sources are used, actual or perceived discrepancies can arise. Sometimes this is due to the location of the data collector, e.g., Windows, SQL Server, or the disk array. Other times, it is due to the collection rate and whether the information is a simple recording of continuously incremented […]

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Using Common Table Expressions to Improve Query Performance

By Jeffry Schwartz | Advice , Intermediate , Performance Tuning , SQL Development , SQL Server

-by Jeffry Schwartz Queries with multiple join clauses create particularly difficult issues when they perform poorly. Join ordering is extremely important because if a join creates a huge interim result set at the beginning of the query execution, SQL Server must continue to handle this result set until it can be trimmed down with filtering […]

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The Pros & Cons of Hyperthreading

By Jeffry Schwartz | Advice , Miscellaneous , SQL Administration , Windows

— By Jeff Schwartz Hyperthreading is one of those features that most IT personnel have heard about, but many do not understand exactly what it does or why it may improve or degrade the performance of their servers. Although hyperthreaded processors have been available for many years, the confusion surrounding it is as commonplace today […]

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Introduction to SQL Server Execution Plans

By Jeffry Schwartz | Miscellaneous , Performance Tuning , SQL Server

Recently, a coworker asked me about a query performance problem that had suddenly arisen as they so often do. During testing, this particular query had performed extremely quickly, but when it was shown to a C-level person, it dragged terribly making this impatient person wait 80 seconds for the answer to come back. We all […]

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