[mythtv] mythbackend 0.22-fixes problem with duplicate database connection name

Roger James roger at beardandsandals.co.uk
Sat Mar 13 12:47:16 UTC 2010

On 08/03/2010 12:58, Roger James wrote:
> On 03/03/2010 13:39, Roger James wrote:
>> On 02/03/2010 21:02, Jim Stichnoth wrote:
>>> On Tue, Mar 2, 2010 at 11:35 AM, Roger James
>>> <roger at beardandsandals.co.uk>  wrote:
>>>> I think I will just apply your split of m_connID to my 0.22-fixes 
>>>> source
>>>> leaving out the rest of your patch and see what happens. It looks 
>>>> pretty
>>>> benign.
>>> I think you would be safe applying the entire r23057 changeset
>>> (http://svn.mythtv.org/trac/changeset/23057?format=diff&new=23057).
>>> I'm not sure why it was never applied to 0.22-fixes.  As an added
>>> benefit, those 5-second freeze-ups will go away.
>>> Jim
>> I am a great believer in minimal changes. I will run with the small 
>> fix for a week or so to see what happens and then try the full 
>> changeset.
>> Thanks,
>> Roger
> Hmm, just had a crash in mythfilldatabase. I have had some crashes 
> before, but not no one reported this way. I don't know if this is 
> related to the change I just made.
> /etc/cron.daily/mythtv-backend:
> credits element: not writing empty content for actor at 
> /usr/share/perl5/XMLTV.pm line 2110.
> *** glibc detected *** mythfilldatabase: corrupted double-linked list: 
> 0x098b50e0 ***
> QMutex::lock: mutex lock failure:
> ======= Backtrace: =========
> /lib/i686/cmov/libc.so.6[0xb51630d9]
> /lib/i686/cmov/libc.so.6[0xb51643af]
> /lib/i686/cmov/libc.so.6(cfree+0x96)[0xb5164826]
> /usr/lib/libmysqlclient_r.so.15(my_no_flags_free+0x21)[0xb333eea1]
> /usr/lib/libmysqlclient_r.so.15(vio_delete+0x30)[0xb336b1a0]
> /usr/lib/libmysqlclient_r.so.15(end_server+0x35)[0xb3366ea5]
> /usr/lib/libmysqlclient_r.so.15(mysql_close+0x8a)[0xb3366f5a]
> /usr/lib/qt4/plugins/sqldrivers/libqsqlmysql.so[0xb34f6018]
> /usr/lib/libQtSql.so.4(_ZN12QSqlDatabase5closeEv+0x16)[0xb5fedc06]
> /usr/lib/libmythdb-0.22.so.0(_ZN12MSqlDatabaseD1Ev+0x39)[0xb64975e9]
I just had another crash in  mythfilldatabase with exactly the same 

*** glibc detected *** mythfilldatabase: corrupted double-linked list: 0x081d6fe0 ***
QMutex::lock: mutex lock failure:
======= Backtrace: =========
======= Memory map: ========

It looks like the m_connID fix appears to have sorted the duplicate 
database connections problem, but may have introduced another problem 
elsewhere. I will leave it in, as I can live with mythfilldatabase 
occasionally falling over!

However, I have just realised that I made another chnage recently and 
that was to run the debug version. Maybe these fails were happening all 
the time and not being trapped in the non debug version.


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