SQL Server Statistics: Charting Volatile Data And Density Vector Values

  Summary: Tony O’Grady, a Microsoft Premier Field Engineer based in the UK, continues with his second post of 5 advanced articles on charting statistical data with SQL Server.  In this post he explores how changes to the underlying data are reflected in cardinality estimations, explores some scenarios, and introduces the concept of density vectors….


Understanding SQL Server Cardinality Estimations by Charting Histogram to Actual Values

Summary: Tony O’Grady, a Microsoft Premier Field Engineer based in the UK, helps us understand whether or not a SQL dataset is going to produce useful query statistics by looking for patterns in histogram values in comparison to actual values. He introduces SQL Server histograms and explains how SQL Server divides the histogram in ranges…