MyISAM Performance Regression Since 8.0.12 With Table Scans
(Doc ID 2992586.1)
Last updated on DECEMBER 12, 2023
Applies to:
MySQL Server - Version 8.0 and laterInformation in this document applies to any platform.
Symptoms
For queries that read a lot of data from MyISAM tables (*.MYD), such as table scans, there are performance regressions of magnitudes (about 20x slower).
The issue began in 8.0.12.
Changes
Upgrading from 5.5, 5.6, 5.7 to a version after 8.0.12 shows this regression. No other changes in data or queries or optimizer plans.
Cause
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In this Document
Symptoms |
Changes |
Cause |
Solution |
References |