[mythtv-users] MySQL related BE deadlocks - collective wisdom needed

[warpme]

Hi *

Thing which most intrigues me is practically lack of similar reports from other MySQL users.
I do quick search on google and wasn't able to find any reports about hangs in mysql client library.
This almost suggest that my issue is probably not mysql itself derived issue (like bug or missconfig/missusage).
My tests with 3 different Mysql versions (2 major ones) are rather conforming this conclusion.

This suggest me to put more attention on my specifics.
We can think here about 3 areas:
1.Usage
2.HW/SW
3.Content

Ad 1:
Here I'm wonder about resources release (especially in non-standard situations like deadlocked BE or hang FE). 

FE: I have master BE + 3xFE used in sleep/resume. Before putting FE into sleep, script sends every 1 sec. main menu exit command. When after 5 times FE still exists - script give killall mythfrontend. I believe this is OK. Sometimes I have to kill -9 FE as it hangs. Is it possible that I miss something here ?

BE: I have (few per day) crashes of mythpreviewgen (mainly issue of encoding on Polish DVB-T MPEG4). Maybe segfaulting previewgen is not releasing MySQL resources thus leading to internal MySQL resources exhaustion ?
I'm not using any other jobs on BE like commflag or transcode.

Ad2:
OS: I'm on Arch Linux. Arch is rolling release. I'm partially minimizing negative aspects of rolling release by do full system upgrade only when it is really needed (usually when number of packages to manually rebuild is really high). Rule is: don't touch if it is working OK.
MySLQ issue was present with various kernels (2.6.35/2.6.36 & 2.6.38). I tested also Qt4.6.3 and 4.7.3.
MySQL was 5.1.51; 5.1.57 & 5.5.12. No change observed. 

Ad3: Here I mean mainly DB content.
Is it possible that my DB has so specific content (I mean i.e. table sizes) or something else which can cause so strange MySQL behavior ?   
Currently total DB size is approx 370M. In terms of content age DB was initialized 4-5y ago. Is it relevant ?

Hope above analytical view may help to lead somebody to some ideas where to look for more closely ?
br