[mythtv-users] Re: Dying Backend

Larry Taub larryt at gmail.com
Tue May 17 19:40:38 UTC 2005

I could buy that the db writes are the problem. Since my first email, I have 
had two more crashes in the backend. 
 The first occurred right when it was scheduled to record a show a few hours 
ago. I was watching another already recorded, flagged, and transcoded show 
at the time so I assume the playback had no interaction with the db after it 
began. Then, the frontend informed me there was no connection to the backend 
when the playback finished. I reviewed the logs and again there was no 
further info. It appeared to start recording the show then the log ceases, 
leading me to believe it died immediately at that point. 
 The second occurred shortly after. I restarted the backend after reviewing 
the logs and later went into mythweb. I viewed the machine status and saw 
that it had picked up in the middle of a recording and thus had an 
incomplete show. I went to recorded programs and selected to delete the 
file. It deleted the file supposedly but crashed the backend. Luckily, this 
was repeatable. I did this again right now to test it and received the 
unable to connect to backend error messages from mythweb.

On 5/17/05, Gavin Haslett <gavin at nodecaf.net> wrote:
> I say that it's during database writing because if I'm just READING the 
> database it almost never seems to die. Basically I see it when scheduling 
> recordings (mythweb most common, but on occasion through Mythfrontend), 
> deleting recordings (removed record from the database, again most often in 
> Mythweb but still happens in MFD), after running mythfilldatabase (often 
> dies a minute or so after MFD runs), and when recording finishes and 
> commflag is about to start. I should clarify that last one; I run that AFTER 
> recording, not during recording as I'm unsure how happy my AMD 800 would be 
> with that.
> I have noticed that if I just WATCH recordings (a task that doesn't write 
> to the database at all) then it doesn't crash... but what would be the point 
> of that?
> I think part of the backend problems might be database-related. I've had 
> occasional problems with MySQL with my own developed applications where it 
> doesn't seem to commit the writes back to the database files correctly, or 
> takes a lot longer than I expect for it to write. It doesn't seem 
> consistent... I just trap for the error and verify writes now. Sure it slows 
> my code, but it prevents my code from segfaulting after a failed write.
> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org on behalf of Larry Taub
> Sent: Tue 5/17/2005 11:24 AM
> To: mythtv-users at mythtv.org
> Cc:
> Subject: [mythtv-users] Re: Dying Backend
> I am right there with you Gavin. I have been experiencing the same 
> problems
> as you report. I had not noticed the correlation with the database writing
> but I hadn't looked for it either. I have noticed many crashes directly
> relating to scheduling recordings in Mythweb. Also, I recorded about 10
> hours worth of tv yesterday and it worked fine then all of a sudden, it
> crashed on an evening recording. When I woke up this morning, I saw that 
> it
> recorded two late night shows fine and was still running but then it 
> crashed
> on a morning show today. I took the opportunity to upgrade to .18.1 and 
> have
> restarted it. When looking at the logs, nothing seems amiss even when I
> turned up the logging verbosity to all. It just shows that recording is
> starting and then the log ends. I tried turning off the commercial 
> flagging
> while it records and it still crashed. To give another data point, I am
> running off the atrpms install of mythtv.
> Larry
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