[mythtv-users] Mythtv database requirements??

[Jim Abernathy]

On 3/29/20 8:54 PM, Stephen Worthington wrote:
> On Sun, 29 Mar 2020 20:31:25 -0400, you wrote:
>
>> On Sun, Mar 29, 2020 at 10:44 AM James Abernathy <jfabernathy at gmail.com>
>> wrote:
>>
>>>
>>> On Sun, Mar 29, 2020 at 9:29 AM Stephen Worthington <
>>> stephen_agent at jsw.gen.nz> wrote:
>>>
>>>> On Sun, 29 Mar 2020 07:21:17 -0400, you wrote:
>>>>
>>>>> So I know mythtv uses MySQL which has supposedly transitioned to mariadb
>>>>> over time, but it's basically the same mysql commands. I think???
>>>>>
>>>>> So to compare what I have on 2 systems I found some puzzling results, at
>>>>> least to me.
>>>>>
>>>>> _System 1_ is Xubuntu 18.04.4 installed recently and mythtv v31
>>>>> installed today.
>>>>>
>>>>> It has mysql-client-5.7, mysql-client-core-5.7, mysql-server-5.7,
>>>>> mysql-server-core-5.7 installed.
>>>>>
>>>>> if has no packages by the name mariadb, or maria installed.
>>>>>
>>>>> _System 2_ is an Ubuntu 18.04 Server which started on mythtv 29, moved
>>>>> to 30, and not 31.
>>>>>
>>>>> It does NOT have mysql-client-5.7, mysql-client-core-5.7,
>>>>> mysql-server-5.7, mysql-server-core-5.7 installed.
>>>>>
>>>>> It has mysql-common installed.
>>>>>
>>>>> It has mariadb-client-10.0, mariadb-client-core-10.0,
>>>>> mariadb-server-10.0, mariadb-server-core-10.0, and mariadb-common
>>>> installed.
>>>>> Not sure why I see the difference and wonder if this is the reason some
>>>>> of the database scripts that run during mythtv updates fail for syntax
>>>>> reasons??
>>>>>
>>>>> Jim A
>>>> Unless something has changed recently, Ubuntu installs MySQL by
>>>> default, so when you install MythTV, it sees MySQL present and is
>>>> happy.  If you install MythTV on a Ubuntu system with neither MySQL
>>>> nor MariaDB installed, the MythTV packages specify MySQL first, so
>>>> MySQL gets installed.  So the only way you get MythTV running with
>>>> MariaDB on Ubuntu is if you have manually chosen to either install
>>>> MariaDB before you installed MythTV (recommended), or have later
>>>> installed MariaDB which will automatically uninstall MySQL.  If you do
>>>> the latter, you normally get a message that the database versions are
>>>> out of step and MariaDB is unable to convert the mythconverg database.
>>>> So you have to reinstall MySQL, do a backup of mythconverg, install
>>>> MariaDB again, create a new mythconverg database and set up its access
>>>> credentials, then restore your backed up copy of mythconverg.  A very
>>>> tedious process I have done more than once, hence why I recommend
>>>> installing MariaDB before installing MythTV if at all possible.
>>>>
>>>> When MariaDB is installed, mysql-common remains installed as there are
>>>> other packages that require it.  It only really creates a three config
>>>> files under /etc/mysql plus documentation files and /usr/share/lintian
>>>> files, so it is not a worry.
>>>>
>>>> My first thought is to wait for Bill to come up with a solution for
>>> updating a system with the mariadb version that Ubuntu 18.04 uses. I plan
>>> on staying on Ubuntu 18.04 LTS until 2023 unless the Covid-19 kills me
>>> first.
>>>
>>> BTW, I can't remember how mariadb got installed because none of my install
>>> instructions have that written down.
>>>
>>> However, I'm a guy who likes to stay on standard software so I don't get
>>> caught by normal assumptions.  All my mythtv databases, backups and
>>> recordings, etc are on a set of 2 RAID mirrors, i.e. 4 drives. I've read
>>> that If you create a new Xubuntu 18.04 install and it will see the 2 RAID
>>> mirrors and know how to use them. I'd just have to add the mounts in
>>> /etc/fstab.  Then I could restore the backed up mythconverg and go from
>>> there.
>>>
>>> Obviously, I have both RAIDs backed up to external e-SATA drive so if the
>>> shit hits the fan I can rebuild.  I even have a clonezilla image of my boot
>>> drive /dev/sda.
>>>
>>> Thoughts on doing this to get back to standard??
>>> Jim A
>>>
>> I just went through this exercise.  As part of my social distancing, I just
>> migrated my MythTV backend from a physical EL6 machine to an Ubuntu 18 LTS
>> VM on Unraid.  The EL6 machine was running MariaDB, yet when I built the
>> Ubuntu machine, as Stephen stated, the package manager dragged in MySQL 5.7
>> I think, rather than MariaDB 10, which is what I was expecting to see.
>> Anyway, when I tried to import the mythconverg dump file from the old
>> machine, it failed on the points Bill made.
>>
>> To get around this, did the following on the new VM:  1) uninstall mythtv,
>> 2) uninstall mysql, 3) install mariadb, then 4) reinstall mythtv.
>>
>> Relatively easy process.  After that, the mythconverg dump file was
>> successfully imported and all is well with the world.

I appreciate all this education. So the surprising part, if I understand 
what has been said here, is that a database backup using 
mythconverg_backup_jsw.pl from a system running MariaDB 10.1 cannot be 
successfully restored on a new system that has MySQL 5.7?

I would have thought that while there are some command structure 
difference between the 2 the backup and restore would have been one of 
the simpler functions that would have worked.

BTW, it looks like Bill has a fix for my update issue.

Jim A