著者: Craig Sanders 日付: To: dmo-discussion 題目: Re: mythtv 0.28+fixes20161017-dmo1 packages are uninstallable
On Tue, Oct 25, 2016 at 01:14:07PM +0200, Stephan Seitz wrote: > On Di, Okt 25, 2016 at 08:45:42 +1100, Craig Sanders wrote:
> > in any case, mariadb is NOT a drop-in replacement for mysql.
>
> Sorry, that was my impression from the devel mailing list. After all
> there are people who prefer to have only one mysql flavour in Debian.
>
> And both share the same directory layout, the same initscript, etc.
given that they can't read and write the same files, the fact that they use
the same directory is a serious bug. mysql should use /var/lib/mysql, and
mariadb should use /var/lib/mariadb, with a conversion tool.
> Or maybe we have a different definition of drop-in replacement.
for a database, being able to read and write the same files is an absolute
minimum requirement. mysql won't/can't use db files created by mariadb.
mariadb can read some versions of db files created by mysql (and, IIRC, can
even write some).
failing that, a foolproof and thoroughly tested bi-directional conversion
tool, used as part of the postinst. e.g. a scripted backup to text, modify the
backup if required with sed or perl etc, and then restore into the other db.
this does not currently exist within debian.
> If you have a default-mta package depending on exim4 then installing it
> would remove your postfix installation.
default-mta is generic. installing default-exim would not remove exim and
install postfix, would it?
default-mysql is specific. mysql is not mariadb and mariadb is not mysql -
they're similar, much closer to each other than e.g. postgres is to either of
them, but still not the same.
> The question is if a package should only depend on such a default-* package.
well, taking official debian packages as examples, the answer is clearly no.
> Should a fresh installation of MythTV install mariadb oder mysql?
don't care, as long as it works. what do the mythtv devs say about
mariadb compatibility?
