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

Michael T. Dean mtdean at thirdcontact.com
Tue Mar 2 18:24:16 UTC 2010

On 03/02/2010 01:17 PM, Roger James wrote:
> I have been recently seeing a problem with mythbackend (0.22-fixes rev 
> 23482) reporting that the database connection had gone away and some 
> (all?) database transactions being rejected with a "Driver not loaded" 
> error. The common factor behind these failures seems be that they all 
> start after the following QSqlDatabasePrivate messages are logged.
> QSqlDatabasePrivate::removeDatabase: connection 'DBManager5' is still 
> in use, all queries will cease to work.
> QSqlDatabasePrivate::addDatabase: duplicate connection name 
> 'DBManager5', old connection removed.
> 2010-02-28 05:32:54.876 New DB connection, total: 6
> 2010-02-28 05:32:54.877 Connected to database 'mythconverg' at host: myth
> 2010-02-28 05:32:54.878 MSqlDatabase::OpenDatabase(), db object is not 
> valid!
> QSqlQuery::exec: database not open
> QSqlQuery::exec: database not open
> 2010-02-28 05:32:54.933 Driver error was [1/-1]:
> Driver not loaded
> Database error was:
> Driver not loaded
> This leaves the backend in a confused state where it appears that some 
> database transactions are failing are and I suspect some are still 
> working. Subsquent new recordings appear in the new recordings list 
> but but have no file associated with them. My guess is that database 
> connections "DBManager0" to "DBManager4" are still working but the old 
> "DBManager5" is now broken.
> I do not recollect having this problem on my old single processor 
> backend system. I think I have only seen it on my new quad core fast 
> processor system. But I cannot be certain.
> The problem usually seems to occur when the system is just idling 
> doing EIT scans. But I have it occur twice when three recordings tried 
> to start at the same time.
> The only similar problem I can find is 
> http://svn.mythtv.org/trac/ticket/7836. But this is reported as a 
> frontend problem. I wonder if the same bug in MDBManager could be 
> causing my problem.
> Any one seen this or got any ideas what is causing it.

Perhaps related to http://svn.mythtv.org/trac/ticket/6544 (and 
http://svn.mythtv.org/trac/ticket/6887 ), and is in code that could 
affect any MythTV application.  We haven't gotten any useful leads on 
tracking down the issue causing #6544 , so any help you can provide is 
greatly appreciated.


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