Upgrade of mythtv backend, xubuntu 18.04 LTS -> 20.04 LTS

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yawlhoo
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Upgrade of mythtv backend, xubuntu 18.04 LTS -> 20.04 LTS

Post by yawlhoo » Mon May 04, 2020 11:28 pm

This morning I gathered my courage and upgraded my v31 mythtv backend running on xubuntu 18.04 LTS, to 20.04LTS.

At the finish of the upgrade and after a reboot, I found that mysql would not run. Googling the error messages led to the following change in /etc/mysql/my.cnf:
===
# * Query Cache Configuration
#
# 20200504 - causing problems, comment out (?)
#query_cache_limit = 1M
#query_cache_size = 16M
===

after which I was able to start mysql.

apache2 (mythweb depends on this) would not start, which led to the rather horrible fix in /etc/apache2/mods-enabled/php7.2.load:
===
# Conflicts: php5
# Depends: mpm_prefork
# 20200504 - kinda crazy, substitute libphp7.4.so for libphp7.2.so
#LoadModule php7_module /usr/lib/apache2/modules/libphp7.2.so
LoadModule php7_module /usr/lib/apache2/modules/libphp7.4.so
===
then I could start apache2 and mythweb worked.

With these fixes in place everything else seems OK, although I wouldn't be surprised to uncover other, less obvious problems as time goes on.

I'm posting this as information for anyone else contemplating such an upgrade.

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bill6502
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Re: Upgrade of mythtv backend, xubuntu 18.04 LTS -> 20.04 LTS

Post by bill6502 » Wed May 06, 2020 3:28 pm

The php solution should be done automatically (I'd remove the 'horrible' one.)

A packaging fix was just pushed. Based on the above, you'll want to do:
sudo a2enmod php7.4
Last edited by bill6502 on Wed May 06, 2020 4:01 pm, edited 1 time in total.
Reason: php7.4, not php.7.4

yawlhoo
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Re: Upgrade of mythtv backend, xubuntu 18.04 LTS -> 20.04 LTS

Post by yawlhoo » Wed May 06, 2020 3:58 pm

I did an apt update and as you mention, a lot of new php packages show up:
===
libapache2-mod-php7.4/focal-updates,focal-security 7.4.3-4ubuntu1.1 amd64 [upgradable from: 7.4.3-4ubuntu1]
php7.4-cli/focal-updates,focal-security 7.4.3-4ubuntu1.1 amd64 [upgradable from: 7.4.3-4ubuntu1]
php7.4-common/focal-updates,focal-security 7.4.3-4ubuntu1.1 amd64 [upgradable from: 7.4.3-4ubuntu1]
php7.4-json/focal-updates,focal-security 7.4.3-4ubuntu1.1 amd64 [upgradable from: 7.4.3-4ubuntu1]
php7.4-mysql/focal-updates,focal-security 7.4.3-4ubuntu1.1 amd64 [upgradable from: 7.4.3-4ubuntu1]
php7.4-opcache/focal-updates,focal-security 7.4.3-4ubuntu1.1 amd64 [upgradable from: 7.4.3-4ubuntu1]
php7.4-readline/focal-updates,focal-security 7.4.3-4ubuntu1.1 amd64 [upgradable from: 7.4.3-4ubuntu1]
===
however, after their install and a reboot, doing as you further suggest yields an error:
===
$ sudo a2enmod php.7.4
ERROR: Module php.7.4 does not exist!
===
and removing my tongue-in-cheek fix makes it so apache2 will not start.

There's some deeper problem here, but what it is is not completely clear to me. Too bad, since after posting my original message I noticed further problems with mythweb, deleting programs and listing subcategories of recorded programs.

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bill6502
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Re: Upgrade of mythtv backend, xubuntu 18.04 LTS -> 20.04 LTS

Post by bill6502 » Wed May 06, 2020 4:03 pm

Fortunately, the fix just released doesn't have the typo (which I just fixed) above.

yawlhoo
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Re: Upgrade of mythtv backend, xubuntu 18.04 LTS -> 20.04 LTS

Post by yawlhoo » Wed May 06, 2020 4:23 pm

Thanks for the information, now a2enmod works, apache2 restarts without any crazy quilt patching in files.

But the some problems remain: deleting programs in mythweb doesn't work, and changing the recordings list from "all programs" to sub-entries doesn't work either.

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bill6502
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Re: Upgrade of mythtv backend, xubuntu 18.04 LTS -> 20.04 LTS

Post by bill6502 » Wed May 06, 2020 9:39 pm

The query_cache_limit = 1M and query_cache_size = 16M don't exist in the packaging
tree, never have.

It appears to me that they were introduced in a MythTV user's mailing list and then (or perhaps
additionally) added to the MythTV Wikis. I found four pages and changed all to put ***s next
them as well as a warning. Plus, the v31 Release Notes now have a warning. All reference
the MySQL page: https://dev.mysql.com/doc/relnotes/mysq ... on-removal

I have both settings in an 'old' 18.04 .cnf file. They weren't in my 19.10 configuration and mysqld.service
started up OK after I upgraded to 20.04 this afternoon.

Thanks for the tip.

[I don't know the answer to your other two observations.]

yawlhoo
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Re: Upgrade of mythtv backend, xubuntu 18.04 LTS -> 20.04 LTS

Post by yawlhoo » Wed May 06, 2020 10:16 pm

Thanks for this information.

I don't know where or when the my.cnf file originated, but perhaps these options appearing in my 18.04 file simply didn't cause any problems prior to 20.04. Then during the upgrade, when I was presented with the option of either keeping my current file or allowing its replacement, I chose keeping it (which usually is presented as the default), and then these options caused havoc.

The mythweb delete and listing problems are not show stoppers, at least for the moment.

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