- Course
SQL Server: Common Query Tuning Problems and Solutions - Part 1
Learn to recognize and diagnose numerous types of SQL Server query performance problems. This course is perfect for developers, DBAs, and anyone responsible for SQL Server, from SQL Server 2005 onward.
Intermediate
- Course
SQL Server: Common Query Tuning Problems and Solutions - Part 1
Learn to recognize and diagnose numerous types of SQL Server query performance problems. This course is perfect for developers, DBAs, and anyone responsible for SQL Server, from SQL Server 2005 onward.
Intermediate
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What you'll learn
There are a wide variety of common performance problems that you will encounter when query tuning. Part 1 of this two-part course begins by showing how to validate query execution assumptions around statistics and cardinality in order to ensure you're troubleshooting the true root cause of a query performance issue. You'll then learn about common areas where bad assumptions can occur that negatively impact overall query performance, and about common problems and solutions related to being imprecise when querying a database. The course is very demo-centric, with lots of practical tips and tricks you'll be able to apply in your environment. This course is perfect for developers, DBAs, and anyone responsible for query performance tuning on SQL Server, from SQL Server 2005 onward.
SQL Server: Common Query Tuning Problems and Solutions - Part 1
Intermediate
Table of contents
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Module Introduction | 53s
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Downstream Impact of Bad Assumptions | 1m 16s
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Cardinality Estimation and Predicates | 1m 1s
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Selectivity | 43s
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Query Cardinality Questions | 54s
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Cardinality Estimate Inputs | 38s
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Statistics | 41s
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Demo: DBCC SHOW_STATISTICS STAT_HEADER | 3m 20s
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Demo: DBCC SHOW_STATISTICS DENSITY_VECTOR | 1m 46s
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Demo: DBCC SHOW_STATISTICS HISTOGRAM | 3m 19s
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Demo: Histogram Direct Step Hit | 2m 17s
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Demo: Scaling the Estimate | 3m 35s
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Demo: Histogram Intra-Step Hit | 2m 57s
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Demo: Density Vector With an Unknown Runtime Value | 3m 53s
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Demo: Parameter Sniffed Value Estimation | 3m 45s
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Demo: Distinct Value Estimation | 1m 42s
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Impact to Query Execution and Performance | 41s
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Identifying Bad Assumptions - 1 | 45s
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Demo: Viewing Estimated Vs. Actual Row Counts | 3m 51s
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Identifying Bad Assumptions - 2 | 41s
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Demo: sys.dm_exec_query_profiles | 1m 45s
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Demo: Root-level Skews via sys.dm_exec_query_stats | 4m 49s
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What Variance is Problematic? | 54s
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Module Summary | 33s
Joe Sack is a Principal Program Manager in the SQL Server and Azure SQL Database product team at Microsoft, with a focus on query processing. With over 19 years of experience in the industry, Joe is an author and speaker, specializing in performance tuning and optimization.