Re: Documentation for the new pooling and XA support in pax-jdbc on master

2016-11-03 Thread Guillaume Nodet 
Yes, all in flight transactions will remain in-flight until the transaction
manager can heuristically determine that they should be rolled back or
committed, which happen when the transaction manager is informed about the
state of the various transactional resources (in our case, the JDBC
connection).
So if the JDBC connection pool does not recover, the transactions that were
in flight at the time of the crash will never be committed or rolled back.
Unfortunately, the recovery can only be done using interfaces that are
specific to a given transaction manager, hence the pax-jdbc-pool-aries and
pax-jdbc-pool-narayana which can support the aries/geronimo and narayana
transaction manager respectively.

2016-11-03 11:55 GMT+01:00 Christian Schneider :

> I fully agree.. The even bigger problem is that people do not really
> understand what recoverable means at all.
> Until recently my understanding was that without recovery all running
> transactions would simply be rolled back in case of a crash .. but this
> does not seem to be the case.
>
> Luckily I met Tim Ward at eclipsecon last week and he explained to me what
> happens with and without recovery but we need to spread the word more about
> this.
>
> So if I understood correctly the problem without recovery is that if the
> server crashes while one resource in an XA transaction is already committed
> and the other is not then
> it will remain in this way.
>

> So I think some people can live with it as it is a rare case but it is
> really important to make people aware of the risk so they can make an
> informed decision.
>
> Christian
>
>
> On 03.11.2016 11:47, Guillaume Nodet wrote:
>
> I think we should clearly document the level of safety using those pooling
> mechanism.
> Afaik, hikari and dbcp2 do not support automatic transaction recovery, the
> only combinations I'm aware of are:
>  *  aries transaction manager + pax-jdbc-pooling-aries
>  * narayana transaction manager + pax-jdbc-pooling-narayana
>
> I think this is really important to document, as people may wrongly think
> they are using something safe (because of XA) while it's not really in case
> of a crash.
>
>
>
> 2016-11-03 11:32 GMT+01:00 Christian Schneider :
>
>> I have documented how the new pooling and XA support works.
>>
>> I think the new support is much more straightforward to use and gives
>> better error reporting.
>>
>> For example in the old pooling support if you use the pooling and xa
>> enabled DSF "H2-pool-xa" and forget to install a TransactionManager or the
>> pooling module the
>> DataSource is simply not created. There is no error in the log as the
>> config module can not know if the enhanced DSF is just not yet there or
>> will never come up.
>>
>> In the new pooling and XA support there will be a good error in the log
>> if either the pooling or the TransactionManager are missing.
>>
>> See
>>
>> https://ops4j1.jira.com/wiki/display/PAXJDBC/Pooling+and+XA+
>> support+in+1.0.0
>>
>> Christian
>>
>> --
>> Christian Schneider
>> http://www.liquid-reality.de
>>
>> Open Source Architect
>> http://www.talend.com
>>
>> --
>> --
>> --
>> OPS4J - http://www.ops4j.org - ops4j@googlegroups.com
>>
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>
>
>
> --
> 
> Guillaume Nodet
> 
> Red Hat, Open Source Integration
>
> Email: gno...@redhat.com
> Web: http://fusesource.com
> Blog: http://gnodet.blogspot.com/
>
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>
>
> --
> Christian Schneiderhttp://www.liquid-reality.de
>
> Open Source Architecthttp://www.talend.com
>
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Blog: http://gnodet.blogspot.com/

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Re: Documentation for the new pooling and XA support in pax-jdbc on master

2016-11-03 Thread Christian Schneider 
I fully agree.. The even bigger problem is that people do not really 
understand what recoverable means at all.
Until recently my understanding was that without recovery all running 
transactions would simply be rolled back in case of a crash .. but this 
does not seem to be the case.


Luckily I met Tim Ward at eclipsecon last week and he explained to me 
what happens with and without recovery but we need to spread the word 
more about this.


So if I understood correctly the problem without recovery is that if the 
server crashes while one resource in an XA transaction is already 
committed and the other is not then

it will remain in this way.

So I think some people can live with it as it is a rare case but it is 
really important to make people aware of the risk so they can make an 
informed decision.


Christian

On 03.11.2016 11:47, Guillaume Nodet wrote:
I think we should clearly document the level of safety using those 
pooling mechanism.
Afaik, hikari and dbcp2 do not support automatic transaction recovery, 
the only combinations I'm aware of are:

 *  aries transaction manager + pax-jdbc-pooling-aries
 * narayana transaction manager + pax-jdbc-pooling-narayana

I think this is really important to document, as people may wrongly 
think they are using something safe (because of XA) while it's not 
really in case of a crash.




2016-11-03 11:32 GMT+01:00 Christian Schneider 
>:


I have documented how the new pooling and XA support works.

I think the new support is much more straightforward to use and
gives better error reporting.

For example in the old pooling support if you use the pooling and
xa enabled DSF "H2-pool-xa" and forget to install a
TransactionManager or the pooling module the
DataSource is simply not created. There is no error in the log as
the config module can not know if the enhanced DSF is just not yet
there or will never come up.

In the new pooling and XA support there will be a good error in
the log if either the pooling or the TransactionManager are missing.

See

https://ops4j1.jira.com/wiki/display/PAXJDBC/Pooling+and+XA+support+in+1.0.0



Christian

-- 
Christian Schneider

http://www.liquid-reality.de

Open Source Architect
http://www.talend.com

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Red Hat, Open Source Integration

Email: gno...@redhat.com 
Web: http://fusesource.com 
Blog: http://gnodet.blogspot.com/

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Christian Schneider
http://www.liquid-reality.de

Open Source Architect
http://www.talend.com

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Re: Documentation for the new pooling and XA support in pax-jdbc on master

2016-11-03 Thread Guillaume Nodet 
I think we should clearly document the level of safety using those pooling
mechanism.
Afaik, hikari and dbcp2 do not support automatic transaction recovery, the
only combinations I'm aware of are:
 *  aries transaction manager + pax-jdbc-pooling-aries
 * narayana transaction manager + pax-jdbc-pooling-narayana

I think this is really important to document, as people may wrongly think
they are using something safe (because of XA) while it's not really in case
of a crash.



2016-11-03 11:32 GMT+01:00 Christian Schneider :

> I have documented how the new pooling and XA support works.
>
> I think the new support is much more straightforward to use and gives
> better error reporting.
>
> For example in the old pooling support if you use the pooling and xa
> enabled DSF "H2-pool-xa" and forget to install a TransactionManager or the
> pooling module the
> DataSource is simply not created. There is no error in the log as the
> config module can not know if the enhanced DSF is just not yet there or
> will never come up.
>
> In the new pooling and XA support there will be a good error in the log if
> either the pooling or the TransactionManager are missing.
>
> See
>
> https://ops4j1.jira.com/wiki/display/PAXJDBC/Pooling+and+XA+
> support+in+1.0.0
>
> Christian
>
> --
> Christian Schneider
> http://www.liquid-reality.de
>
> Open Source Architect
> http://www.talend.com
>
> --
> --
> --
> OPS4J - http://www.ops4j.org - ops4j@googlegroups.com
>
> --- You received this message because you are subscribed to the Google
> Groups "OPS4J" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to ops4j+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
>



-- 

Guillaume Nodet

Red Hat, Open Source Integration

Email: gno...@redhat.com
Web: http://fusesource.com
Blog: http://gnodet.blogspot.com/

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Documentation for the new pooling and XA support in pax-jdbc on master

2016-11-03 Thread Christian Schneider 

I have documented how the new pooling and XA support works.

I think the new support is much more straightforward to use and gives 
better error reporting.


For example in the old pooling support if you use the pooling and xa 
enabled DSF "H2-pool-xa" and forget to install a TransactionManager or 
the pooling module the
DataSource is simply not created. There is no error in the log as the 
config module can not know if the enhanced DSF is just not yet there or 
will never come up.


In the new pooling and XA support there will be a good error in the log 
if either the pooling or the TransactionManager are missing.


See

https://ops4j1.jira.com/wiki/display/PAXJDBC/Pooling+and+XA+support+in+1.0.0

Christian

--
Christian Schneider
http://www.liquid-reality.de

Open Source Architect
http://www.talend.com

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