All Posts by Jeffry Schwartz

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Jan 07

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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Oct 15

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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Feb 16

Top PerfMon Performance Counters for Determining Causes of Slow Response Times

By Jeffry Schwartz | Performance Tuning , SQL Server , Windows

Introduction Have you ever been placed in the position of being forced to address user complaints about how slow the system is performing without really knowing exactly where to begin looking? Some analysts begin with Task Manager or viewing the Windows event log. Others who are working with SQL Server search the ErrorLog for problems […]

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