Two MYSQL processes are being seen after upgrading to 22.2.x

Products

• CA Spectrum

Issue/Introduction

We have upgraded from 21.2.8 to 22.2.8 and have noticed that we are now seeing two MYSQL processes that are running.

Everything is working fine, but we are surprised to see why 2 MYSQL processes are now running in Spectrum from the SPECTROSERVER.

Environment

Spectrum 22.2.x

Cause

Since MySQL 8.0.12, the mysqld process launches a second copy of itself. 

Resolution

Since MySQL 8.0.12, the mysqld process launches a second copy of itself. The parent process monitors the child for restart requests (to support the SQL RESTART statement). The child process does all the work of running a MySQL server - you can see that the child process has a much larger memory footprint, typically associated with the innodb buffer pool.

Additional Information

It is possible to prevent this "two instances" behaviour and only run a single instance of mysqld by using the --no-monitor command line option, but then the SQL RESTART statement only shuts down the mysqld process without starting a new one.

See https://dev.mysql.com/doc/refman/8.0/en/server-options.html#option_mysqld_no-monitor