Statistics & Query Planning: Overview

Understand how database statistics drive query optimizer decisions

Read and interpret histograms, distinct value counts, and NULL fractions

Diagnose cardinality estimation errors causing bad query plans

Update statistics after bulk loads to prevent performance degradation

Use extended statistics for correlated columns and multi-column predicates

Identify when statistics are stale and causing suboptimal plans

Understand how database statistics drive query optimizer decisions

Read and interpret histograms, distinct value counts, and NULL fractions

Diagnose cardinality estimation errors causing bad query plans

Update statistics after bulk loads to prevent performance degradation

Use extended statistics for correlated columns and multi-column predicates

Identify when statistics are stale and causing suboptimal plans