[mythtv-users] mythbackend not responding on port 6543

[Stephen Worthington]

On Tue, 15 Nov 2016 01:33:53 +1300, you wrote:

Today, I decided to eliminate as many possibilities for the cause of
my problem as possible.  I have two boot partitions on my SSD, so I
installed a fresh copy of Mythbuntu 16.04.1 on the other partition,
did no updates to the software as installed from the 16.04.1 image,
and booted on the older of the two kernels installed.  I did the least
changes I could to get the system able to work using my hardware and
database.  That involved:

- Getting the networking going (uninstalling network-manager and
setting up static IP addresses)
- Changing from mysql to mariadb
- Putting the timezone data into the mysql database
- Setting up permissions for MythTV to use the mythconverg database
- Copying across my config.xml file that matches my database

After that, I restored the latest database backup, and tried running
mythbackend.  But I got exactly the same problem - it would not talk
properly to mythfrontend, and would not record or do much of anything
that it should.

So I then found an ancient backup I had done of my database just
before I upgraded from 0.26 to 0.27, and restored that.  I ran
mythtv-setup to upgrade the schema, and then without running
mythbackend I ran mythfrontend to upgrade the mythmusic schema.  The
upgrades worked without any problems.  So then I started mythbackend
and mythfrontend, and everything seemed to be working normally.

The conclusion I reached from this is that the problem is related to
my database somehow, rather than the versions of any software I am
running.  Something about my current database triggers the problem.

My database is huge - the latest backup file is 1,221,579,067 bytes
(1.13 Gibytes).  So it could be something related to that.  Or it
could be some setting inside the database that is the problem.  It is
unlikely to have corrupt database structure, as it passes all the
mysqlcheck tests without any problems, and in any case it has just
been restored from the text SQL backup file, rather than been running
in the database files for a long time.

I think my next move is to try restoring some other backups to see if
they work.  Otherwise all I really have left as a way of finding the
problem is compiling MythTV for myself and putting debugging code into
it.  Since I do not know my way around the mythbackend code, that
would take quite a while.

There is also one new symptom I have noticed.  I have SMB/CIFS
networking set up so that my Windows box can access the drives on my
MythTV box.  When mythbackend is running in its not-responding state,
Windows is unable to access the MythTV box.  Access via CIFS from my
test PC (Mythbuntu) still works normally.  If I stop mythbackend, the
access from my Windows box again works normally.