ITPUB

Feb 21, 2023 · Databases

How MySQL Implements File Sorting: Internals, Modes, and Optimizations

This article explains MySQL's file‑sort mechanism in depth, covering the sort buffer, handling of long sort keys, three sort modes, priority‑queue and read‑rnd‑buffer optimizations, internal vs. external sorting, descending sort implementation, and how to inspect details with optimizer trace.