Liangxu Linux

May 25, 2022 · Databases

Understanding MySQL Internal vs External Temporary Tables and Their Storage Engines

This article explains the two kinds of MySQL temporary tables—external and internal—covers the scenarios that trigger their creation, details how MySQL chooses MEMORY, MyISAM or InnoDB storage engines based on system variables and data size, and describes indexing, hash‑field fallbacks, and optimization hints such as SQL_SMALL_RESULT and SQL_BIG_RESULT.