Performance tuning dimensional databases

This section describes how to tune the performance of your queries and to understand data distribution statistics.

Query execution plans
When a SELECT statement or other DML operation is submitted to the database server, the query execution optimizer designs a query execution plan. The query execution optimizer is often referenced as the query optimizer.
Data distribution statistics
Data distribution statistics are stored in the system catalog for use by the query optimizer when it designs query execution plans. These statistics, together with other information, enable the optimizer to estimate the relative costs among the execution plans that the optimizer is considering for a specific query. Distribution statistics that the optimizer examines for tables that are referenced in queries can include column distribution statistics for the table and for its indexes, as well as fragment-level statistics, if the database server has gathered statistics for individual table or index fragments.

Parent topic: Dimensional databases

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