[mythtv-users] what is mythtv's preferred/recommended database?

[Gary Buhrmaster]

On Sat, Dec 11, 2021 at 12:48 PM John Hoyt <john.hoyt at gmail.com> wrote:
>
> A while back the mythtv wiki stated a preference for mysql as the default database.  More recently I have been observing that most folks on this list have moved on to mariadb (this could be a vocal minority).
>
> What is the preferred/recommended database these days?

The last statement from the MythTV elders has been
that the officially supported database is mysql, and that
mariadb is tolerated to the extent possible.  There have
been occasional suggestions from those that are not
deciders to reverse that (mariadb first, mysql tolerated),
but the elders have not changed the official word(s) at
this time, and those that want some assurance of future
assistance should stick with the official list of supported
external tools.

As has also been previously mentioned, while both
mysql and mariadb are mostly compatible, there is,
and is increasing, divergence in their functions as
time has passed after the fork.

So far the MythTV developers have managed to
adjust, as needed, to the changes in both/either
engine, although even upstream projects (Qt is an
example) have gotten caught by the changes and
divergence, which can result in periods of
brokenness until the fixes get rolled out.  Trying to
predict the future is difficult, but I suspect that the
MythTV project will be able to continue to support
both mysql and mariadb going forward, so, in
some ways, support vs. toleration is a distinction
without a difference, until it is not.

It should be noted that except for one distro (that
has a "marketing" arrangement with Oracle (i.e.
money is exchanged)) pretty much all distros
semi-default to mariadb (typically offering the user
the choice to install mysql if they want/need,
as the one distro that defaults to mysql allows
one to install mariadb if one wants/needs)

However, the one distro that defaults to mysql is,
according to smolt, the distro reported as being
used by more MythTV users.  That suggests that
the project has a good reason to stay with mysql
as the "default"/"recommended" engine.

>From a systems level perspective, there are
certainly benchmarks that can show either
mysql or mariadb perform better in particular
use cases.  MythTV simply does not demand
enough from the database to make any real
world difference on most systems.

There may be individuals who prefer one over
the other due to their experience with one
(or because they have other apps running
on their systems that require a specific one).
For many MythTV users, the db engine is
"install and (mostly) forget", so it (again)
likely does not matter which is the default.




<opinions>

For various reasons, I run mariadb, with
a non-default engine (innodb in my use
case), which has been carefully tuned
for that particular system (which has
other uses).  There are a couple of known
specific incompatibilities between myisam
and innodb, but they do not impact my
(or when I checked many many years ago,
MythTV's) uses.  I also accept that I am
running a non-supported configuration, and
will never ask for support on the MythTV
lists (as this is a case of "you break it, you
own it").  Those that want assistance (i.e.
are not confident of their DBA skills) should
not do what I am doing, and should stick
with the official supported list.

Personally, as a baby step, I would like to
see the project move to mariadb first and
consider to change the default engine to aria,
which is a (mostly) compatible replacement
for myisam which includes crash tolerance
(as crashed tables are among the common
common user support issues).  However
(and very importantly) I do not know of
anyone who has done so and run an
extensive regression test against all the
uses that MythTV has (although I seem to
recall there was some interest by someone
that I mentioned the aria engine to).

</opinions>