[jbossts-issues] [JBoss JIRA] (JBTM-3325) Create a way to close XAResource at the end of the recovery cycle processing
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https://issues.redhat.com/browse/JBTM-3325?page=com.atlassian.jira.plugin...
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Michael Musgrove commented on JBTM-3325:
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A few of points:
1. It is normally the application servers job to close connections. This method can
potentially break assumptions made by the app server.
2. The resource adaptor can be shared by multiple threads so all other threads that are
potentially using the adaptor need to be notified. Agroal probably knows how to handle
that but can we be sure that other adaptors do too. You may argue that you have made it
configurable, but the accompanying PR sets this behaviour globally so all resource types
will be expected to handle the close correctly (and be expected to work with the
application servers' connection management policies). Again, basically it is the app
servers job to close connections.
3. A TM can have a connection to an RM via more than one resource adaptor and the
'XAResource#isSameRM' method is provided to tell the TM when that is the case.
What effect will your closing of one of them have on the other resource adaptors that
connect to the same RM?
4. Finally TMENDRSCAN is not to tell the resource adaptor that the scan has ended. It is
the resource adaptors job to tell the TM when the scan has finished and it does that in
'int xa_recover(..)' by returning an int that the caller uses to determine whether
the passed in array is full or not. If the caller did not supply a big enough array then
the caller can keep calling the recover method until the cursor has reached the end of the
list of prepared branches. The caller tells the resource to reset its cursor using the
TMENDRSCAN flag.
Remark: JTA is a layer over XA and is somewhat vague on the usage of this flag, in fact
the spec does not even discuss it. I would expect it is never used since in a Java
environment the resource returns a Java array from the recover call whereas in the XA API
the caller supplies the array.
I think this issue should be discussed within the community before making the change.
Create a way to close XAResource at the end of the recovery cycle
processing
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Key: JBTM-3325
URL: https://issues.redhat.com/browse/JBTM-3325
Project: JBoss Transaction Manager
Issue Type: Enhancement
Components: JTA
Affects Versions: 5.10.5.Final
Reporter: Ondrej Chaloupka
Assignee: Ondrej Chaloupka
Priority: Major
From discussions about Narayana integration to Agroal (https://agroal.github.io/) there
came an idea how to make easier for Agroal to integrate with Narayana recovery
processing.
Usually (or at least Agroal does so) the brand new {{XAResource}} is provided from the
call of the {{XAResourceRecovery}}
(https://github.com/jbosstm/jboss-transaction-spi/blob/7.6.0.Final/src/mai...).
aka. Agroal implements the {{XAResourceRecovery}} and register it with the Narayana with
adding it to with
https://github.com/jbosstm/jboss-transaction-spi/blob/7.6.0.Final/src/mai...
to be used in {{XARecoveryModule}}.
When the periodic recovery cycle ends the {{XAResource}} is not used (next time the
recovery processing calls the {{XAResourceRecovery#getXAResources()}} to get the resource
for scanning again). The transaction manager announces that the scan ended with call
{{XAResource.recover(XAResource.TMENDRSCAN)}} (this is an internal to how Narayana
works).
It would be beneficial provide an option that Narayana closes {{XAResource}}s at the end
of the recovery cycle when Narayana does not plan to use it again.
The idea is to check if the {{XAResource}} is {{AutoCloseable}} and if so then the
{{XAResource}} is closed at the end of the recovery cycle processing.
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