Batch Mode Processing in SQL Server 2019
Oct 12,
2021
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 […]
Some Query Hints: Undocumented, But Interesting
,
2021
It’s a commonly held misconception, even among some knowledgeable SQL folks, that the SQL Server query optimizer evaluates different ways of executing a query and goes with the query plan that yields the lowest estimated cost. As is often the case with misconceptions, this one is not so much wrong as a bit oversimplified. The […]
SQL Server 2014 New Features: Cardinality Estimation in the Query Optimizer
May 25,
2015
Is it Better or Worse? What is Cardinality Estimation A fancy-sounding phrase, “cardinality estimation” basically means “guessing how many”. The ability of the query optimizer to select a superior query plan from among many possibilities requires the estimation of how many rows will be extracted from the participating tables and how these rows will be […]
