The Most Important Performance Factor in SQL Server

The most important factor in SQL Server that affects query performance is statistics.

When you execute a query, the optimizer needs to come up with the best possible execution plan for it, and it needs good and accurate statistics for that. Without them, the optimizer is blind, and your query performance will suffer.

In this session, we will get to know statistics, as well as the cardinality estimator – the SQL Server component that is responsible for estimating row counts based on statistics.

We will cover all types of statistics, such as column vs. index statistics, single-column vs. multi-column, filtered statistics, incremental statistics, and more. 

We will look at scan vs. seek operations, and we will examine how execution plans are made.