Re: dbconfig-common: near future change in dependency stack

[Clint Byrum <spamaps@debian.org>]

Excerpts from The Wanderer's message of 2016-01-30 15:49:51 -0800:
> On 2016-01-30 at 08:49, Clint Byrum wrote:
> 
> > Excerpts from The Wanderer's message of 2016-01-30 04:28:42 -0800:
> > 
> >> On 2016-01-30 at 04:51, Paul Gevers wrote:
> 
> >>> Actually, I don't think that is in scope of dbconfig-common. I
> >>> would rather expect that MariaDB would provide that
> >>> functionality. It is required for more packages and situations
> >>> than just those supported by dbconfig-common.
> >> 
> >> Are there even cases where this is necessary?
> >> 
> >> Within the last year, I encountered an unacceptable - but
> >> intentional - change in the MySQL client interface, so I removed
> >> the MySQL packages and installed the MariaDB ones.
> > 
> > Which client interface would that be? libmysqlclient18 is still
> > provided by mysql, even if you install MariaDB.
> 
> The one invoked with the command 'mysql'.
> 
> The underlying library is still the same (though as far as I can see,
> the dependency chain from mariadb-client-core-10.0 to libmysqlclient18
> only exists because libdbd-mysql-perl depends on the latter, so I'm not
> convinced that ), but the client itself behaves differently.
> 
> The specific UI change which drove me away from "pure" MySQL was the
> change in line-editing library, away from readline, so that my habitual
> "jump around the line while editing the query" practices would no longer
> function - and, as far as I recall, there was no suitable replacement. I
> dug around for a while looking for a way to turn the readline behaviors
> back on, started digging into the process of building my own packages
> which revert to the old behavior, then discovered that MariaDB had not
> followed that change and decided to just migrate instead.
> 

Funny story.. they do speak the same protocol, and you can use the
mariadb client with mysql server just fine. :)

> >> My existing database was picked up and used without issues; the 
> >> transition was, on that level, pretty much seamless as far as I
> >> recall. I might have needed to re-apply some configuration tweaks
> >> in different config files, but nothing more than that.
> > 
> > This is a one-way trip as of MariaDB 10. MariaDB 5.5 was compatible
> > with MySQL 5.5 and allowed using the same on-disk files. But MySQL
> > may not know how to read all of the files produced by MariaDB 10+. So
> > I would not count on this working again in the future. They're truly
> > forks, and you will need to backup/restore to make this work.
> 
> This is valuable to know for future reference, though I'm not sure I'm
> ever likely to need or want to migrate in that direction between the
> two; I was only still on MySQL rather than MariaDB out of inertia.
> 

MySQL is adding features and pushing scale upwards at a very fast rate.
So some users encountering this thread might be in the opposite situation
of needing to go from MariaDB to MySQL.

> Since the topic at hand was specifically migrating from MySQL to
> MariaDB, however, rather than bidirectional migration between the two,
> my question stands: are there cases where migration from MySQL to
> MariaDB needs to be done explicitly per-database?
> 

I don't really understand the context of your question.