mariadb: Job for mariadb.service failed because a fatal signal was delivered to the control process

Please Help! mariadb crashed on debian 10.4 on raspberry4, just made a upgrade from 10.2 to 10.4. But I rebootet after upgrade, all was working after reboot. Crash was 1 hour later.

`/var/log/mysql/error.log 
2020-06-25 15:36:25 0 [Note] InnoDB: 10.3.22 started; log sequence number 17201576; transaction id 150227
2020-06-25 15:36:25 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
2020-06-25 15:36:25 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-06-25 15:36:25 0 [Note] Recovering after a crash using tc.log
2020-06-25 15:36:25 0 [ERROR] Can't init tc log
2020-06-25 15:36:25 0 [ERROR] Aborting`

two hours before:

`2020-06-25 13:57:39 0 [Note] InnoDB: 10.3.22 started; log sequence number 17198243; transaction id 150195
2020-06-25 13:57:39 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
2020-06-25 13:57:39 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-06-25 13:57:39 0 [Note] Server socket created on IP: '127.0.0.1'.
2020-06-25 13:57:39 0 [Note] Reading of all Master_info entries succeeded
2020-06-25 13:57:39 0 [Note] Added new Master_info '' to hash table
2020-06-25 13:57:39 0 [Note] /usr/sbin/mysqld: ready for connections.`

I already moved tc.log:

mv /var/lib/mysql/tc.log /var/lib/mysql/tc.log.bak

does not help!!

root@archivpi:~# service mysql restart
Job for mariadb.service failed because a fatal signal was delivered to the control process.
See "systemctl status mariadb.service" and "journalctl -xe" for details.

Here is systemctl status: I have to write here some text some text some text otherwise not saved. I have to write here some text some text some text otherwise not saved. I have to write here some text some text some text otherwise not saved.

root@archivpi:~# systemctl status mariadb.service
● mariadb.service - MariaDB 10.3.22 database server
   Loaded: loaded (/lib/systemd/system/mariadb.service; enabled; vendor preset: enabled)
   Active: activating (start-pre) since Thu 2020-06-25 16:43:11 CEST; 198ms ago
     Docs: man:mysqld(8)
           https://mariadb.com/kb/en/library/systemd/
  Process: 25326 ExecStartPre=/usr/bin/install -m 755 -o mysql -g root -d /var/run/mysqld (code=exited, status=0/SUCCESS)
  Process: 25327 ExecStartPre=/bin/sh -c systemctl unset-environment _WSREP_START_POSITION (code=exited, status=0/SUCCESS)
Cntrl PID: 25329 (sh)
    Tasks: 4 (limit: 1599)
   Memory: 1.1M
   CGroup: /system.slice/mariadb.service
           ├─25329 /bin/sh -c [ ! -e /usr/bin/galera_recovery ] && VAR= ||   VAR=`/usr/bin/galera_recovery`; [ $? -eq 0 ]   && systemctl set-env
           ├─25330 /bin/sh /usr/bin/galera_recovery
           ├─25341 /bin/sh /usr/bin/galera_recovery
           └─25343 sed -e s;--[^=]*=;;

Jun 25 16:43:11 archivpi systemd[1]: Starting MariaDB 10.3.22 database server...

I have another raspberry here, upgraded to 10.4., too. mariadb works there, similar database. I can look/compair there ... if helps.

Very mysterious was:

root@archivpi:~# aptitude reinstall mariadb-server
Die folgenden Pakete werden ERNEUT INSTALLIERT:
  mariadb-server
Die folgenden teilweise installierten Pakete werden konfiguriert:
  hostapd
0 Pakete aktualisiert, 0 zusätzlich installiert, 1 erneut installiert, 0 werden entfernt und 0 nicht aktualisiert.
0 B/30,8 kB an Archiven müssen heruntergeladen werden. Nach dem Entpacken werden 0 B zusätzlich belegt sein.
(Lese Datenbank ... 129192 Dateien und Verzeichnisse sind derzeit installiert.)
Vorbereitung zum Entpacken von .../mariadb-server_1%3a10.3.22-0+deb10u1_all.deb ...
Entpacken von mariadb-server (1:10.3.22-0+deb10u1) über (1:10.3.22-0+deb10u1) ...
mariadb-server (1:10.3.22-0+deb10u1) wird eingerichtet ...
hostapd (2:2.7+git20190128+0c1e29f-6+deb10u2) wird eingerichtet ...
hostapd.service is a disabled or a static unit not running, not starting it.
/var/lib/dpkg/info/hostapd.postinst: 53: .: Can't open /etc/default/hostapd
dpkg: Fehler beim Bearbeiten des Paketes hostapd (--configure):
 »installiertes hostapd-Skript des Paketes post-installation«-Unterprozess gab den Fehlerwert 127 zurück
Fehler traten auf beim Bearbeiten von:
 hostapd
E: Sub-process /usr/bin/dpkg returned an error code (1)
hostapd (2:2.7+git20190128+0c1e29f-6+deb10u2) wird eingerichtet ...
hostapd.service is a disabled or a static unit not running, not starting it.
/var/lib/dpkg/info/hostapd.postinst: 53: .: Can't open /etc/default/hostapd
dpkg: Fehler beim Bearbeiten des Paketes hostapd (--configure):
 »installiertes hostapd-Skript des Paketes post-installation«-Unterprozess gab den Fehlerwert 127 zurück
Fehler traten auf beim Bearbeiten von:
 hostapd

What has hostapd to do with mariadb?? I copied a empty /etc/default/hostapd from other machine to that raspberry, now hostapd is "satisfied". (maybe error already before, but why ist that a problem when reinstall mariadb-server?

I have another raspberry running with mariadb , also upgraded, but running. I can compair files/ copy files/ ... if useful

Can I reinstall database software without deleting databases? - I have a copy of important database. A second database, not so important, I have no copy.

Thats the complete start-until-crash protocol of /var/log/mysql/mysql.log:

2020-06-25 15:51:16 0 [Note] InnoDB: Using Linux native AIO
2020-06-25 15:51:16 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2020-06-25 15:51:16 0 [Note] InnoDB: Uses event mutexes
2020-06-25 15:51:16 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2020-06-25 15:51:16 0 [Note] InnoDB: Number of pools: 1
2020-06-25 15:51:16 0 [Note] InnoDB: Using generic crc32 instructions
2020-06-25 15:51:17 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
2020-06-25 15:51:17 0 [Note] InnoDB: Completed initialization of buffer pool
2020-06-25 15:51:17 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page \
of setpriority().
2020-06-25 15:51:17 0 [Note] InnoDB: 128 out of 128 rollback segments are active.
2020-06-25 15:51:17 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2020-06-25 15:51:17 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2020-06-25 15:51:17 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2020-06-25 15:51:17 0 [Note] InnoDB: 10.3.22 started; log sequence number 17201594; transaction id 150227
2020-06-25 15:51:17 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
2020-06-25 15:51:17 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-06-25 15:51:17 0 [Note] Recovering after a crash using tc.log
2020-06-25 15:51:17 0 [ERROR] Can't init tc log
2020-06-25 15:51:17 0 [ERROR] Aborting