Re: What led to the design of having multiple option file locations?

Thanks a lot for the explanation, Stewart and Sergei!

Basically the main purpose is to support different conventions such as
Redhat- and Debian-based distributions.

Wait... Isn't this a bad way to do things? I think the right way is to
decide at installation time: figure out the type of system and decide
the location of the configuration file. This makes even less sense
when using pre-compiled mysql packages for specific distribution
(e.g., the ones dedicated for Fedora and Ubuntu via yum or apt-get).

The side-effect of multiple locations is the "inheritance-rewrite"
relations from the parent locations to the child locations. If
/etc/my.cnf is for Fedora and /etc/mysql/mysql.cnf is for Debian. Why
the Debian location has to listen to the Fedora one? :-P

Again, the downside for multiple locations is that it confuses users
(at least myself), especially when someone modifies a parent location.

Best,
Tianyin



On Mon, Nov 10, 2014 at 2:06 AM, Sergei Golubchik <[email protected]> wrote:
> Hi, Stewart!
>
> You got it almost right!
> A couple of comments:
>
> On Nov 10, Stewart Smith wrote:
>> Tianyin Xu <[email protected]> writes:
>> > One special thing for MySQL configuration is that there're multiple
>> > locations for the option files (there're 5 locations both on Windows
>> > and Unix-like platforms),
>> > http://dev.mysql.com/doc/refman/5.5/en/option-files.html
>>
>> /etc/my.cnf largely for historical reasons.
>
> This is also the location of my.cnf in Fedora and I suppose all
> RedHat-based distributions. Not only historical.
>
>> /etc/mysql/my.cnf as the main one as then you can do things such as
>> "include /etc/mysql/*cnf" and have individual components configured in
>> their own files (great for package managers!).
>
> This is the location of my.cnf in Debian, Ubuntu and some other
> distributions (Gentoo, for example).
>
> So, mysqld reads both /etc/my.cnf and /etc/mysql/my.cnf because
> different distributions put my.cnf in different locations.
>
> And, of course, you cannot do "!include /etc/mysql/*cnf".
>
> If you do it from /etc/mysql/my.cnf you'll end up including the same
> file recursively over and over again (unless mysqld has a protection for
> this case, which I doubt). If you do it from some other my.cnf - you'll
> simply !include /etc/mysql/my.cnf twice.
>
> On Redhat/etc one often uses "!includedir /etc/my.cnf.d/", on
> Debian/Ubuntu - "!includedir /etc/mysql/conf.d/"
>
> Besides, "!include" does not support wildcards.
>
>> The SYSCONFDIR/my.cnf and $MYSQL_HOME/my.cnf really just exist to make
>> it easier to have 101 mysql servers running on a single machine sharing
>> some common configuration and some custom configuration.
>>
>> defaults-extra-file so you can on-demand point at some other config file
>> (useful when running benchmarks or experiments or something)
>>
>> and ~/.my.cnf can do things like "i'm a user and i want to set options
>> for my mysql client"
>
> Regards,
> Sergei

-- 
Tianyin XU,
http://cseweb.ucsd.edu/~tixu/

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