[mapguide-internals] Session repository lock under multi-threaded update

Bruce Dechant bruce.dechant at autodesk.com
Wed Jan 5 17:45:21 EST 2011

The problem is that DBXML 2.5.16 always uses a transaction when doing dbxml operations.
Our resource service was for some operations not creating a transaction and this in turn caused dbxml to create one internally - this can be problematic and may have caused the lockups you are seeing. I remember seeing this while doing the dbxml upgrade. I changed the resource service code to follow the dbxml guidelines to always use a transaction for all dbxml operations. With this change the lockups went away. I tested with between 20 and 100 concurrent user loads over the weekend (48+ hours) and there were no lockups and with the new session repository strategy I didn't see any DB_BUSY errors either.


-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org [mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Andreas Morf
Sent: Wednesday, January 05, 2011 3:11 PM
To: 'MapGuide Internals Mail List'
Subject: RE: [mapguide-internals] Session repository lock under multi-threaded update

I saw this many times when I was upgrading to dbxml 2.5.16 which is
especially more sensitive when being called by an untransacted
dbxml-API-operation. After eliminating these in MgResourceService there are
DB_BUSY errors sometimes which I was able to handle in my JAVA Webapi code -
but in my opinion, this could/should be handled by MgResourceService in a
better way...


-----Ursprüngliche Nachricht-----
Von: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] Im Auftrag von Trevor
Gesendet: Mittwoch, 5. Januar 2011 22:19
An: MapGuide Internals Mail List
Betreff: [mapguide-internals] Session repository lock under multi-threaded


Has anyone experienced session repository lockup when executing 4+
concurrent calls to SetResource using different session ids?  The
SetResource call is creating new resources and not updating old resources.


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