Re: Bad performance on MySQL 8.0 compared to 5.7

[Peter Brawley]

Thanks for the uploads.

What RAM is available to MySQL?

The query ...

select * from sys.memory_global_total;

... returns NULL on both systems. Did you run these as a user without access to sys.memory_global_total ?

Off the top ...

- innodb_buffer_pool_size is the default, 128MB. It should be about 75% of RAM. Consider redoing sysbench on both systems with that setting

- neither system had much activity during the uptime periods, could ou supply enough demand at least to fill the innodb buffer pool more than once over a period of at least 2 hrs?

- your sysbench results resemble https://www.percona.com/blog/2019/02/21/mysql-8-is-not-always-faster-than-mysql-5-7/ results with 8.0.15 3.5 yrs ago

- see https://dba.stackexchange.com/questions/216352/inserts-in-mysql-8-are-slower-than-inserts-in-mysql-5-7



Edited 3 time(s). Last edit at 08/26/2022 03:42AM by Peter Brawley.