[mythtv-commits] Ticket #13121: Sat>IP client support

MythTV noreply at mythtv.org
Sun May 2 11:50:10 UTC 2021

#13121: Sat>IP client support
 Reporter:  cg@…                |          Owner:  Klaas de Waal
     Type:  Patch - Feature     |         Status:  assigned
 Priority:  minor               |      Milestone:  32.0
Component:  MythTV - Recording  |        Version:  Master Head
 Severity:  low                 |     Resolution:
 Keywords:                      |  Ticket locked:  0

Comment (by Klaas de Waal):

 My backup script, dating from 2011, makes a backup with
 mythconverg_backup.pl but it also makes a second backup with mysqldump on
 the entire mythconverg database.
 The backup with mysqldump on the entire database causes the problems as
 this blocks the Housekeeper task. The Housekeeper tasks then blocks the
 complete mythbackend.

 What happens is this:
 - Sat>IP recording in progress
 - The backup with mysqldump of the entire database starts
 - Sat>IP recording continues
 - The Housekeeper starts (it does this every minute)
 - After the last log message line of the Housekeeper mythbackend is frozen
 - Sat>IP recording stops
 - The backup with mysqldump finishes
 - mythbackend unfreezes
 - Sat>IP fails with "sendMessage read: RTSP/1.0 454 Session Not Found" for
 the keepAlive message.

 The Sat>IP box has a session timeout of 60 seconds; therefore a keepAlive
 message is sent every 30 seconds.
 The keepAlive messages are not sent when mythbackend is frozen and thus
 the session times out when the frozen period is long enough.
 The Sat>IP box is then idle while mythbackend thinks it is still

 This problem showed up when I started to use the Sat>IP on my living room
 system which has a much larger database than my development system and
 hence the backup takes much longer.

 The first solution, removing the mysqldump of the complete database and
 using only the mythconverg_backup.pl, is now under test.

 A better solution is to use the backup scripts of fe31nz: do first a
 backup to a SSD and then later do the compression and the copying.
 To be tested.

 The Sat>IP code can be improved so that it can recover from the "Session
 Not Found".
 If this happens the current recording should be terminated and it should
 be possible to start a new recording.

 Also the Housekeeper task can be investigated. After starting the
 mysqldump backup the recording continues, but only when the Housekeeper
 task runs mythbackend completely freezes. Even when the Houskeeper task is
 blocked it should not need to block recordings.

Ticket URL: <https://code.mythtv.org/trac/ticket/13121#comment:65>
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