InnoDB Tables Uses More Memory In 5.7 Than 5.6
Last updated on JULY 13, 2017
Applies to:MySQL Server - Version 5.7 and later
Information in this document applies to any platform.
For a MySQL instance with many InnoDB tables and/or partitions, after upgrading to MySQL Server 5.7, the memory usage is higher than before the upgrade. Enabling the memory instrumentation in the Performance Schema shows the main memory usage comes from InnoDB's heap usage (memory/innodb/mem0mem):
Additionally there are many allocations and deallocations of memory/innodb/mem0mem which together with the added memory usage can cause poor performance of some queries, particularly scans of for example the information_schema.TABLES table which causes many partitioned tables to be opened.
MySQL was upgraded to MySQL Server 5.7.
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