[mythtv-users] [mythtv] segfault in libmysqlclient.so.21

[Stephen Worthington]

On Tue, 16 Jun 2020 06:41:38 -0400, you wrote:

>I've been following the issue on both this list and at 
>https://bugs.launchpad.net/bugs/1877504
>
>There doesn't appear to be a fix yet?
>
>So my high-level questions are:
>
>1. Since I have mythtv v31 on Ubuntu 18.04 with mariadb, should I avoid 
>moving to Ubuntu 20.04 when the 20.04.1 is released with an upgrade 
>path? seems like the answer is "yes"
>
>2. Since this issue is mariadb specific and I really have no need to be 
>on mariadb specifically, could I convert to v31 and Ubuntu 20.04 doing 
>the following:
>
>- backup mythconverg db (mythconverg_backup.pl) on current system and 
>all recordings.
>
>- fresh install of Ubuntu 20.04 and mythtv v31 with standard mysql that 
>the mythtv install pulls in.
>
>- restore all files and mythconverg db
>
>*Alternatively I thought about this sequence:*
>
>- backup mythconverg db as above.
>
>- uninstall mythtv and mariadb-server
>
>- upgrade Ubuntu to 20.04.1 and install mythtv v31 with default mysql
>
>- restore mythconverg db
>
>Any thoughts other than, "if it ain't broke don't fix it" :-)
>
>Jim A

The procedure for changing from MariaDB to MySQL is (as best I
remember it from the last time I did it):

1) Backup your database.

2) Work out what all your users and their GRANTs are.  Run these
commands:

sudo mysql
select distinct concat('SHOW GRANTS FOR ', QUOTE(user), '@',
QUOTE(host), ';') as query from mysql.user;

That gives you a list of commands to run.  Run each of those commands
in turn.  That give you all the grants for all the users.  Keep a copy
of the results.

3) Install the MySQL client and server packages.  This should
uninstall the corresponding MariaDB packages, and may also require
uninstalling MythTV and any other packages dependent on MariaDB/MySQL.

4) Reinstall all the dependent packages (such as MythTV) that got
uninstalled in 3).

5) Create a mythconverg database by running these commands:

sudo mysql
source /usr/share/mythtv/sql/mc.sql

This step sets up mythconverg with the necessary GRANTs and the proper
character set.  If you also had other users and GRANTs, you will also
need to do them again here - see the output from step 2).

6) Restore your database.

Steps 2) and 5) are the ones that catch out people who do this for the
first time.

To convert from MySQL to MariaDB, just reverse the process - the steps
are otherwise the same.