Monitoring and Updating Statistics

Statistics is an important concept in query optimization. Generating statistics is the process of collecting metadata about your data—such as the number of rows and the size of tables—which can be used as additional inputs by the Structured Query Language (SQL) engine to optimize query plans.

Note

This section primarily focuses on the Monitor and update statistics about data across a system concept of the DP-203: Data Engineering on Microsoft Azure exam.

For example, if two tables have to be joined and one table is exceedingly small, the SQL engine can use this statistical information to pick a query plan that works best for such highly skewed tables. The Synapse SQL pool engine uses something known as Cost-Based Optimizers (CBOs). These optimizers choose the least expensive query plan from a set of query plans that can be generated for a given SQL script.

Now, look at how you can create statistics for both Synapse dedicated...