Deep Dive: Understanding B-Tree Indexes in PostgreSQL Internals

Understanding B-Tree Indexes in PostgreSQL: A Comprehensive Guide– Part 1

I explore the inner mechanics of B-Tree indexes in PostgreSQL to help you optimize query performance on large tables. We examine how data is physically stored in pages, the role of ctid in locating rows, and the balanced tree structure that ensures efficient retrieval. Understanding these foundational concepts is key to leveraging indexes effectively and avoiding slow sequential scans.

"When a simple search is conducted on a table without any indexes, PostgreSQL defaults to a sequential scan, iterating over every data entry until conditions match."