Bug #88360 Documentation about systemd and mysqld-debug is incomplete and wrong
Submitted: 4 Nov 2017 11:40 Modified: 4 Nov 2017 15:09
Reporter: Daniël van Eeden (OCA) Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:5.7.20 OS:Any
Assigned to: CPU Architecture:Any

[4 Nov 2017 11:40] Daniël van Eeden
Description:
Page: https://dev.mysql.com/doc/refman/5.7/en/mysqld-safe.html#option_mysqld_safe_mysqld

"--mysqld=prog_name

The name of the server program (in the ledir directory) that you want to start. This option is needed if you use the MySQL binary distribution but have the data directory outside of the binary distribution. If mysqld_safe cannot find the server, use the --ledir option to indicate the path name to the directory where the server is located.

As of MySQL 5.7.15, this option is accepted only on the command line, not in option files. On platforms that use systemd, the value can be specified in the value of MYSQLD_OPTS. See Section 2.5.10, “Managing MySQL Server with systemd”."

With systemd this can't be set in MYSQLD_OPTS, but specifying an alternative "ExecStart=" works with "journalctl edit mysqld"
This is stored in /etc/systemd/system/mysqld.service.d/override.conf
This is documented on https://dev.mysql.com/doc/refman/5.7/en/using-systemd.html

However https://dev.mysql.com/doc/refman/5.7/en/using-systemd.html doesn't mention mysqld-debug explicitly (I think it should).
I think it should also mention that mysqld-debug should use an alternative plugin_dir (See Bug #88088 )

How to repeat:
See description
[4 Nov 2017 11:55] Daniël van Eeden
Related:
Bug #88363
Bug #88362
Bug #88361
Bug #88359
[4 Nov 2017 15:09] Miguel Solorzano
Thank you for the bug report.