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Re: [reSIProcate] asynchronous registration handling


Hi Justin,

Thanks for your reply. I've still got a couple of questions (sorry if I'm missing something):

1. I presume you're suggesting that we reject the registration in RegistrationHandler::onXxx(). How does the information that the RegistrationPersistenceManager has failed reach the handler? The only way I can see is to keep a map from aor to status, provide a public interface to get at it, and cast the persistence manager to the appropriate subclass in order to decide whether to accept or reject the registration.

2. What happens if, say, there is a connection problem when we try to roll back to the previous registration details, or if we fail to take out the lock even (since the database is shared)?

It sounds as though your new implementation will make this a lot easier and clearer.

Thanks again,

Rob.


Justin Matthews wrote:
Hi Rob,

Currently you would handle this by trapping all database failures in your
persistence manager and then call ServerRegistration::reject().  All the db
operations are performance before the calls to onRefresh,onRemove,onAdd,etc.
If you reject() the registration, then ServerRegistration tries to roll back
the changes by removing the registration (via removeAor()) and then
re-applying the original list that it saved (via addAor).

The implementation I am working on will allow more flexible error handling
without blocking the DUM thread, will not require roll back if the
registration is rejected and will require fewer DB calls.  I should have
more details in a few days.

Thanks,

-justin

-----Original Message-----
From: resiprocate-devel-bounces@xxxxxxxxxxxxxxx
[mailto:resiprocate-devel-bounces@xxxxxxxxxxxxxxx] On Behalf Of Robert
Backhouse
Sent: Thursday, March 12, 2009 9:53 AM
To: 'resiprocate-devel'
Subject: Re: [reSIProcate] asynchronous registration handling

Hi,

I have a separate but related question. In the last few days I have also been having trouble in this area while trying to implement a database-based RegistrationPersistenceManager.

My problem is that there doesn't seem to be any mechanism to cope with an action/query failing - if there is a problem with the database connection, the SQL syntax, or just a random deadlock or transaction timeout then I can't see a way to fail the registration.

I presume some people must have successfully written database backed RegistrationPersistenceManager implementations - can anyone explain how they dealt with SQL exceptions without a response to signify failure or a suitable exception to throw?

Otherwise, if the ServerRegistration logic is being rewritten, do you think this would be a sensible opportunity to support failures from the RegistrationPersistenceManager in some way?

Thanks,

Rob.


2009/3/9 Justin Matthews <jmatthewsr@xxxxxxxxx <mailto:jmatthewsr@xxxxxxxxx>>

Hi,

I am looking at adding asynchronous REGISTER handling in DUM. Has anyone thought about or actually implemented this? There are some notes in DialogSet.cxx about moving REGISTER handling to DialogUsageManager, would these mean converting REGISTER handling to be a DumFeature? Would this makes things easier to post back responses to a DUM feature as opposed to implementing some kind of postback to a ServerRegistration? Basically I need to send the DB queries off to another thread to avoid blocking.

Also, is anyone else interested in this?

Thanks,

justin



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Robert Backhouse <robertb@xxxxxxxxxxxxx>
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