SQLPerformance.com is about providing innovative and practical solutions for improving SQL Server performance. Whether you are running a 3rd party application database where very little can be changed, or you are a DBA at a site where getting the application developers to change anything is next to impossible, industry experts including Paul Randal, Jonathan Kehayias, Erin Stellato and Paul White will cover both the "how" and the "why."

Articles by SQLPerformance.com

Itzik Ben-Gan explains the mechanics behind some different approaches to solving gaps and islands problems in T-SQL.
September 12, 2018 | SQLPerformance.com | T-SQL 0
Glenn Berry lays out a convincing argument to upgrade to a modern version of SQL Server -- considering not only the platform improvements but also changes to Windows, storage, and hardware.
Jonathan Kehayias shares insight about new UDF information in showplan, and shows that only some tools will show it (SSMS 17+ & SentryOne Plan Explorer).
Erin Stellato shows how to extract patterns and anti-patterns from the plan cache, Query Store, or the SentryOne database.
In the conclusion of his series on grouping and aggregation costs, Itzik Ben-Gan reveals some of the math behind seek vs. scan decisions.
Glenn Berry of SQLskills.com describes the different tiers for Azure SQL Database, and what you get for your money in each case.
Andy Mallon dispels the myth that SQL Server maintains some kind of query result cache to make future executions of the same query faster.
Jonathan Kehayias of SQLskills.com shares his story of an unusual situation with high CLR_MANUAL_EVENT waits and how he resolved it.
July 18, 2018 | SQLPerformance.com | Wait Stats 0
In the fourth installment of his series on optimization thresholds, Itzik Ben-Gan looks at how SQL Server applies costs to parallel operations.
For his first guest post on SQLPerformance.com, Bert Wagner describes the pros and cons of join elimination in SQL Server.
June 18, 2018 | SQLPerformance.com | T-SQL 0
Itzik Ben-Gan dissects the Hash Match (Aggregate) algorithm in his latest post in a series on SQL Server optimization thresholds.
Tim Radney goes into detail about why baselines are important, and how metrics you collect now can help you solve future problems.
Continuing his series on optimization thresholds, Itzik Ben-Gan dives into the costs behind stream aggregates when the data needs to be sorted first.
Glenn Berry discusses a number of compelling reasons why, if you are choosing between SQL Server 2016 or SQL Server 2017, you should choose the newer version.
For his first post on SQLPerformance.com, Itzik Ben-Gan shows you how to reverse engineer optimizer costing for a Stream Aggregate operator.

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