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From Craig L Russell <Craig.Russ...@Sun.COM>
Subject Re: Possible problem with ddl with only a jta-datasource and sequences
Date Wed, 25 Apr 2007 22:48:06 GMT
Hi Partick,

On Apr 25, 2007, at 11:41 AM, Patrick Linskey wrote:

>> That's why we have two datasources for an EMF. One is the
>> transactional datasource that gives you connections
>> automatically enlisted in your transactional EM; the other
>> gives you connections that are never enlisted and can be used
>> for nontransactional queries, nontransactional sequences etc.
>> The TSR is only of use for the enlisted datasource/connection.
>
> That's one approach for out-of-band work. But, there are other ways to
> do such work also, without requiring multiple datasources. For  
> example,
> suspending the current tx, starting a new one, doing the work,
> committing, and resuming the old one is a workable solution, if you  
> have
> access to the tx.

My comment was that the two-datasource approach works for all  
configurations that I know of, and doesn't depend on the existence of  
mutliple non-standardized interfaces by which the transaction service  
providers have granted grudging access to their transaction control  
mechanism.

There was agreement with TSR on the basic functionality that all  
transaction service providers would support. Some vendors pushed back  
when we tried to expand the functionality.

If "everyone" has extra functionality why is it so hard to come to a  
common set of features? There's no intrinsic value in one app server  
giving access via Proprietary Interface 1 and another app server  
giving the same access via Proprietary Interface 2.

What we were able to get with TSR interface was agreement as to how  
to deal with transaction-enlisted connections. Perhaps we need to go  
back (Umbrella JSR for Java EE 6) and make a bigger fuss over the  
additional needed functionality.

Craig
>
> -Patrick
>
> -- 
> Patrick Linskey
> BEA Systems, Inc.
> ______________________________________________________________________ 
> _
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>> -----Original Message-----
>> From: Craig.Russell@Sun.COM [mailto:Craig.Russell@Sun.COM]
>> Sent: Wednesday, April 25, 2007 10:05 AM
>> To: open-jpa-dev@incubator.apache.org
>> Subject: Re: Possible problem with ddl with only a
>> jta-datasource and sequences
>>
>>
>> On Apr 24, 2007, at 11:38 AM, Marc Prud'hommeaux wrote:
>>
>>> David-
>>>
>>>> Does this seem like a reasonable explanation?
>>>
>>> That sounds right to me.
>>>
>>> Note that if we ever update OpenJPA to depend solely on the
>>> TransactionSynchronizationRegistry, then we won't be able
>> to do things
>>> like suspending the transactions and resuming it later with the
>>> jta-datasource.
>>
>> That's why we have two datasources for an EMF. One is the
>> transactional datasource that gives you connections
>> automatically enlisted in your transactional EM; the other
>> gives you connections that are never enlisted and can be used
>> for nontransactional queries, nontransactional sequences etc.
>> The TSR is only of use for the enlisted datasource/connection.
>>
>> Craig
>>>
>>>
>>> On Apr 24, 2007, at 10:52 AM, David Jencks wrote:
>>>
>>>> Using derby, jta transactions (in geronimo), a table sequence,
>>>> autocreation of tables, and only a jta-datasource, I get errors
>>>> complaining that the sequence table doesn't exist.
>>>>
>>>> Caused by: org.apache.openjpa.lib.jdbc.ReportingSQLException:
>>>> Table/View 'OPENJPASEQ' does not exist. {SELECT
>> SEQUENCE_VALUE FROM
>>>> OPENJPASEQ WHERE ID = ? FOR UPDATE WITH RR} [code=20000,
>> state=42X05]
>>>>
>>>> If I supply a non-jta-datasource everything works fine.
>>>>
>>>> My current theory about why this is happening is that the ddl to
>>>> create all the tables is executed in a connection from the jta-
>>>> datasource that's enrolled in a jta transaction.  Then we
>> go to get
>>>> an id from the sequence, the jta transaction is suspended,
>> and a new
>>>> tx is started, in which the ddl is not visible since the jta tx
>>>> wasn't committed. (apparently ddl in derby is transactional)
>>>>
>>>> Does this seem like a reasonable explanation?
>>>>
>>>> I'm going to look for a way to run the ddl inside a separate
>>>> transaction that can be committed, the same as how sequences work
>>>> without a non-jta-datasource.  One way to do this would be to
>>>> package the work up in a Runnable and execute it in an
>>>> appropriate transactional environment.  It might be easier to
>>>> understand if the sequence code had a similar implementation.
>>>>
>>>> thanks
>>>> david jencks
>>>>
>>>
>>
>> Craig Russell
>> Architect, Sun Java Enterprise System http://java.sun.com/products/ 
>> jdo
>> 408 276-5638 mailto:Craig.Russell@sun.com P.S. A good JDO? O, Gasp!
>>
>>
>
> Notice:  This email message, together with any attachments, may  
> contain information  of  BEA Systems,  Inc.,  its subsidiaries   
> and  affiliated entities,  that may be confidential,  proprietary,   
> copyrighted  and/or legally privileged, and is intended solely for  
> the use of the individual or entity named in this message. If you  
> are not the intended recipient, and have received this message in  
> error, please immediately return this by email and then delete it.

Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:Craig.Russell@sun.com
P.S. A good JDO? O, Gasp!


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