Aikesheng Open Source Community
Nov 20, 2020 · Databases
Optimizing a Slow MySQL 5.7 Query for Detecting Tables Without Primary or Unique Keys
This article examines why a MySQL 5.7 query that finds tables lacking primary or unique keys runs extremely slowly, demonstrates an experiment reproducing the issue, analyzes the optimizer's subquery rewrite, and shows how adding hints and materialization reduces execution time from over 16 seconds to under one second.
INFORMATION_SCHEMAPerformanceQuery Optimization
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