A practical guide to database indexes in PostgreSQL covering how B-tree indexes work internally, how to create single-column, composite, partial, expression, and unique indexes, and how to use EXPLAIN ANALYZE to measure query performance. Also covers other index types (Hash, GIN, GiST, BRIN), index management (listing, sizing, finding unused, dropping, rebuilding), common mistakes that prevent index usage (function wrapping, type casting, leading wildcards, low selectivity), and best practices for indexing deliberately based on actual query patterns.
Table of contents
Table of ContentsPrerequisitesWhy Do You Need Indexes?How Indexes Work Under the HoodHow to Create Your First IndexHow to Use EXPLAIN ANALYZE to Measure PerformanceTypes of Indexes in PostgreSQLHow to Create a Composite IndexHow to Create a Partial IndexHow to Create an Expression IndexHow to Create a Unique IndexHow to Manage IndexesWhen Indexes Hurt Instead of HelpCommon Mistakes That Prevent Index UsageBest Practices for IndexingConclusionSort: