von Uwe Ricken | Dez. 21, 2024 | 300, DB Engine, SQL Blog, Statistiken
This week I was called out twice to an incident at a customer’s site where a massive blocking problem occurred in the web shop. The root cause was the AUTO_UPDATE STATISTICS option. One blog article is not enough to explain the complexity of this problem....
von Uwe Ricken | Dez. 9, 2024 | 200, DB Engine, SQL Blog
JOIN Elimination in Microsoft SQL Server is an optimization technique with foreign key constraints where the query engine removes redundant JOIN operations during query execution. This occurs when the data from the joined table is not used in the SELECT clause or any...
von Uwe Ricken | Dez. 1, 2024 | DB Engine, Optimierung, SQL Blog
My first article on using foreign key constraints in databases included the claim that using them slows down an application. This article addresses the claim that a Foreign Key Constraint use locks and can cause Deadlocks and thus slow down applications. Claim Foreign...
von Uwe Ricken | Nov. 25, 2024 | DB Engine, SQL Blog
When revising one of my popular sessions on scenarios in which indexes no longer help, one of the topics covered was foreign key constraints for data integrity and JOIN eliminiation. During my research, I came across various arguments from developers who reject...
von Uwe Ricken | Nov. 20, 2024 | DB Engine, Optimierung, SQL Blog, Tipps und Tricks
Unit tests/demos in workshops and conference sessions sometimes require a random key value from an existing table. In this article I present a solution that accomplishes this task quickly and in a resource-efficient manner. Why an existing – random – key?...
von Uwe Ricken | Sep. 26, 2024 | DB Engine, Indexierung, Optimierung, SQL Blog
Wer berechnete Attribute in Tabellen verwendet, sollte sich darüber im Klaren sein, dass unter bestimmten Voraussetzungen die Performance leidet. Dieser Artikel beschreibt die Nachteile, die sich aus „berechneten Attributen“ in Tabellenobjekten ergeben....
