openstack team mailing list archive

[Caitlin Bestler <Caitlin.Bestler@xxxxxxxxxxx>]

Jorge Williams wrote:

>  Push notifications don't make your core system any more complex. You push the change to a message queue and rely on another system to do the work.

That is only true if the messaging system and the core system are largely independent, which could have some implications that would probably be fine for
most human users but could be quite problematic for applications.

Can the push notification system block the core system? If not the push notifications ultimately become unreliable. A human who is not notified that
a given update once in 10,000 times is probably just going to shrug it off.  But an application that needs to know it is looking at the most recent version
of a document before it modifies it is ultimately going to have to rely on polling, or have the notification be built into the core system complete with
throttling of updates when absolutely necessary to ensure that notifications are sent.