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From Dain Sundstrom <>
Subject Re: More questions on runtime schema generation
Date Fri, 27 Apr 2007 16:22:06 GMT
On Apr 26, 2007, at 1:49 PM, David Jencks wrote:

> Thanks for all the comments, I've learned a lot.
> 1. I have a classloader scanning strategy written and apparently  
> working, however it is rather slow at least in geronimo.  Is anyone  
> interested in it, seeing as how its not an appropriate approach in  
> a app server according to Patrick's comment below?  I think it  
> might still be useful as a "last resort" strategy.
> 2. It looks like the best strategy for geronimo to follow is to  
> figure out which jars in an ee app can possibly have persistent  
> classes in them and supply a list of those jars to the  
> PersistenceUnitInfo.  IIUC scanning those jars is already implemented.

IIRC the spec limited the scope of a persistence unit to the jar that  
contains the persistence.xml file, so we shouldn't have to do deep  

> 3. I can't get running ddl on a connection from an XADataSource in  
> a simulated "RequiresNew" transaction to work reliably with derby.   
> The ddl appears to work fine but attempts to read data from the  
> created sequence table hang until the tx times out and derby does  
> not report any deadlocks.  Based on Craig's comments I've added a  
> non-jta-datasource and this seems to be working much better.  Has  
> anyone seen problems like this?  (seems unlikely in this context  
> since i had to modify a bunch of stuff to get to this problem :-)

If the outer transaction has previously read from that table, you  
have created a self deadlock.  Have you checked the sql to make sure  
that there isn't a query that referenced the sequence table?


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