Bad performance on MySQL 8.0 compared to 5.7

[Raphael Yeung]

Hello,

I am a newbie on MySQL.
I am working on a performance testing task comparing between MySQL 8.0 and 5.7.
2 VMs are installed with 5.7 or 8.0 on each side.
Using mysqlslap for benchmark and having the result that 8.0 works slower.
I would like to have some advice.


mysqlslap command used:

###
/usr/local/mysql/bin/mysqlslap \
--no-defaults \
--concurrency=50 \
--iterations=10 \
--engine=innodb \
--auto-generate-sql \
--auto-generate-sql-add-autoincrement \
--auto-generate-sql-load-type=mixed \
--auto-generate-sql-write-number=1000 \
--number-of-queries=100000 \
--host=localhost \
--port=3306 \
--user=root
###

benchmark results:

## 5.7 ##
Benchmark
Running for engine innodb
Average number of seconds to run all queries: 18.146 seconds
Minimum number of seconds to run all queries: 16.727 seconds
Maximum number of seconds to run all queries: 22.460 seconds
Number of clients running queries: 50
Average number of queries per client: 2000
######

## 8.0 ##
Benchmark
Running for engine innodb
Average number of seconds to run all queries: 26.603 seconds
Minimum number of seconds to run all queries: 24.865 seconds
Maximum number of seconds to run all queries: 28.906 seconds
Number of clients running queries: 50
Average number of queries per client: 2000
######

Here is the testing environment:
Machine: Azure VM (spec: Standard_D2s_v3)
OS: Ubuntu 20.04.4 LTS (Focal Fossa)
MySQL: 5.7.37 / 8.0.30 (both are installed by make install flow)
Data disk: copied a snapshot from a 5.7 DB, created a volume from the snapshot.
The other hardware spec are the same.

######

And the results of "show variables" will be attached in the coming thread.
Thank you for your attention and I hope I can get some help.

Regards,
Raphael