MySQL Forums
Forum List  »  Performance

Re: MySQL 8 - terrible performance
Posted by: Hans Meiser
Date: February 13, 2019 03:36AM


yes this is true. But its doesn't matter if i do an upgrade from 5.7 to 8.0 or reinitialise a fresh 8.0 installation. result in both cases is the same.

OS is Ubuntu 18.04
To compare i measured time of same operations on same server with different MySQL Versions.

First server is an average system: 4G/AMD Athlon(tm) 7750 Dual-Core Processor/HDD
mysql was stopped, deleted all data in /var/lib/mysql and run command "mysqld --initialize-insecure --console" after that command i run "mysql_upgrade -s --force" several times.

In both mysql-Versions binlogging is enabled.

tests with mysql 5.7.25

mysqld --initialize-insecure --console
real 0m27,929s
mysql_upgrade -s --force
real 0m48,751s
real 0m32,481s
real 0m33,115s

After that i removed all mysql, installed mysql 8.0.15 and did same procedure with deleting all data, reinitialise and run mysql_upgrade
this is result with mysql 8.0.15
mysqld --initialize-insecure --console
real 1m4,912
mysql_upgrade -s --force
real 10m16,397s
real 9m47,756s
real 9m56,170s

If i activate general-log, i can read inserts line by line ;) . System has only minimal cpu and io-usage during mysql_upgrade. Seems that MySQl is not using full system power.

To compare i used an better server with 48G/Intel(R) Xeon(R) CPU E5645 @ 2.40GHz/SSD

mysql 5.7.25
mysqld --initialize-insecure --console
real 0m2,385s
mysql_upgrade -s --force
real 0m0,956s
real 0m0,901s
real 0m0,855s

mysql 8.0
mysqld --initialize-insecure --console
real 0m5,028s

mysql_upgrade -s --force
real 0m9,673s
real 0m9,503s
real 0m9,381s

You see on better server times are in total better, but we see same time-factor between 5.7 and 8.0

Here is a output of "mysqladmin variables" with current values. we adjust only a few of variables, most of them are default. I cant believe that default variables have that negative influence.

Thanks you for your help. I hope you see something odd in my config or can tell advice to better situation. Iam afraid of having bad performance on production servers.


Options: ReplyQuote

Written By
February 11, 2019 02:09AM
February 11, 2019 10:47AM
February 11, 2019 11:55AM
February 11, 2019 12:52PM
February 11, 2019 08:13PM
February 12, 2019 02:59AM
Re: MySQL 8 - terrible performance
February 13, 2019 03:36AM
February 14, 2019 12:28AM
February 14, 2019 03:33AM
February 15, 2019 03:32AM
February 15, 2019 05:23AM
March 18, 2019 05:19AM

Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.