[mythtv-users] Backend crashing, MySQL related I think

[Stephen Worthington]

On Sun, 8 Oct 2017 02:36:03 +0000, you wrote:

>On 8 October 2017 12:42:06 am "DryHeat122 ." <dryheat122 at gmail.com> wrote:
>
>> I have been suffering increasingly frequent backend crashes lately.  When
>> this happens, restarting the backend does not fix the problem. It takes a
>> reboot to straighten things out, so I'm guessing the problem isn't the
>> backend per se.   mythbackend.log indicates some mysql problems.  Segment
>> below is from where I think the problem starts. Any suggestions how to
>> troubleshoot/fix?
>>
>> Oct  4 15:00:05 steve-EP45-UD3P mythbackend: mythbackend[806]: N Update
>> autoexpire.cpp:264 (CalcParams) AutoExpire: CalcParams(): Max required Free
>> Space: 3.0 GB w/freq: 15 min
>> Oct  4 15:05:43 steve-EP45-UD3P mythbackend: mythbackend[806]: N Expire
>> autoexpire.cpp:264 (CalcParams) AutoExpire: CalcParams(): Max required Free
>> Space: 3.0 GB w/freq: 15 min
>> Oct  4 15:20:43 steve-EP45-UD3P mythbackend: mythbackend[806]: N Expire
>> autoexpire.cpp:264 (CalcParams) AutoExpire: CalcParams(): Max required Free
>> Space: 3.0 GB w/freq: 15 min
>> Oct  4 15:35:43 steve-EP45-UD3P mythbackend: mythbackend[806]: N Expire
>> autoexpire.cpp:264 (CalcParams) AutoExpire: CalcParams(): Max required Free
>> Space: 3.0 GB w/freq: 15 min
>> Oct  4 15:50:43 steve-EP45-UD3P mythbackend: mythbackend[806]: N Expire
>> autoexpire.cpp:264 (CalcParams) AutoExpire: CalcParams(): Max required Free
>> Space: 3.0 GB w/freq: 15 min
>> Oct  4 15:59:00 steve-EP45-UD3P mythbackend: mythbackend[806]: I Scheduler
>> scheduler.cpp:2267 (HandleReschedule) Reschedule requested for PLACE
>> PrepareToRecord
>> Oct  4 16:00:44 steve-EP45-UD3P mythbackend: mythbackend[806]: E TaskQueue
>> mmulticastsocketdevice.cpp:60 (MMulticastSocketDevice)
>> MMulticastSocketDevice(239.255.255.250:68): setsockopt - IP_ADD_MEMBERSHIP
>> #012#011#011#011eno: No such device (19)
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: E TVRecEvent
>> mythdbcon.cpp:864 (prepare) Error preparing query: INSERT INTO recordedseek
>> (chanid, starttime, type, mark, offset) VALUES
>> (2041,'2017-10-04T22:00:00Z',9,102269,5125967392),(2041,'2017-10-04T22:00:00Z',9,102397,5132956856)
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: E TVRecEvent
>> mythdbcon.cpp:866 (prepare) Driver error was [2/2013]:#012QMYSQL3: Unable
>> to prepare statement#012Database error was:#012Lost connection to MySQL
>> server during query
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: E TVRecEvent
>> mythdb.cpp:183 (DBError) DB Error (delta position map insert):#012Query
>> was:#012INSERT INTO recordedseek (chanid, starttime, type, mark, offset)
>> VALUES
>> (2041,'2017-10-04T22:00:00Z',9,102269,5125967392),(2041,'2017-10-04T22:00:00Z',9,102397,5132956856)#012Driver
>> error was [2/2006]:#012QMYSQL: Unable to execute query#012Database error
>> was:#012MySQL server has gone away
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: E TVRecEvent
>> mythdbcon.cpp:229 (OpenDatabase) [DBManager119] Unable to connect to
>> database!
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: E TVRecEvent
>> mythdbcon.cpp:230 (OpenDatabase) Driver error was [1/2003]:#012QMYSQL:
>> Unable to connect#012Database error was:#012Can't connect to MySQL server
>> on '192.168.1.200' (101)
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: I TVRecEvent
>> mythdbcon.cpp:842 (prepare) MySQL server disconnected
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: I TVRecEvent
>> mythdbcon.cpp:638 (exec) MySQL server disconnected
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: E TVRecEvent
>> mythdb.cpp:183 (DBError) DB Error (delta position map insert):#012Query
>> was:#012#012No error type from QSqlError?  Strange...
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: E TVRecEvent
>> mythdbcon.cpp:229 (OpenDatabase) [DBManager119] Unable to connect to
>> database!
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: E TVRecEvent
>> mythdbcon.cpp:230 (OpenDatabase) Driver error was [1/2003]:#012QMYSQL:
>> Unable to connect#012Database error was:#012Can't connect to MySQL server
>> on '192.168.1.200' (101)
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: I TVRecEvent
>> mythdbcon.cpp:842 (prepare) MySQL server disconnected
>> Oct  4 16:14:40 steve-EP45-UD3P mythbackend: mythbackend[806]: I TVRecEvent
>> mythdbcon.cpp:638 (exec) MySQL server disconnected
>>
>>
>>
>Next time if happens check the state of mysql before rebooting. How best to do so will depend on your OS but a quick first check is to see if you can actually login to your mysql instance as the user in your config.xml file.

There are various things that can cause mysql problems.  There may be
some clues in the mysql log files (normally in /var/log or
/var/log/mysql).  I would also check the mythconverg database for any
errors or crashed tables using the optimize_db script.  And before
doing that, also make sure that you have enough free space on the
drive.  You need room for a copy of the largest table's files.  The
largest table is recordedseek, so take a look at
/var/lib/mysql/mythconverg/recordedseek.* and see if you have at least
as much free space as those files take.