Tag: Query plans

Early in 2019, when SQL Server 2019 was a community preview and the release was many many months away, we were delighted to see the performance benefits of batch mode processing for some row data queries (that is, no columnstore index). Now that SQL Server 2019 is being installed in production facilities, and batch mode […]

As a part of our continuing study of SQL Server query plans, we’re going to take a look at some subqueries. This is particularly important, since subqueries are the subject of some fair amount of folklore, and it is important to separate fact from myth. It’s not uncommon to hear someone say “Joins are better […]

In the previous blog, we took a quick look at query plan caching using the classic but still serviceable syscacheobjects view. A serious journey of exploration into the SQL procedure cache must, however, begin with the dynamic management view sys.dm_exec_cached_plans. While this view does provide us with some interesting information in its own right, the […]

The SQL Server Query Optimizer is always of great interest to students taking Learning Tree’s Developing SQL Queries for SQL Server and Developing High-Performance SQL Server Databases courses. Today we’ll look beyond the operators in the query plan and focus our attention on some aspects of the optimization process itself. Optimization is always a balancing […]

Introduction Some of the new features of SQL Server 2016, most notably the Advanced Analytics and Polybase, are unprecedented in earlier versions. In contrast, the Query Store added to SQL Server 2016 doesn’t so much add new features as make the time-honored tasks of query execution monitoring faster, easier, and more convenient. Once turned on […]