Stream: implementers
Topic: Subscription notification frequency
Lloyd McKenzie (Aug 23 2019 at 17:10):
In the new subscription world, is there a mechanism to place limitations on how frequently notifications should happen? E.g. If you don't need anything more frequent than once every 5 minutes, it'd be nice not to get notifications hundreds of times per second...
Lloyd McKenzie (Aug 23 2019 at 17:10):
@Jenni Syed
Jenni Syed (Aug 23 2019 at 18:12):
No, and we've talked about this at previous connectathons. It was something that would have been very tough for a server to take on
Jenni Syed (Aug 23 2019 at 18:12):
Typically, if a system wanted this they would do a since/lastUpdated query on polling, or use an intermediary to "batch" the responses
Jenni Syed (Aug 23 2019 at 18:13):
Some history: https://chat.fhir.org/#narrow/stream/179229-subscriptions/topic/Client.20and.20Server.20delays
Lloyd McKenzie (Aug 23 2019 at 18:23):
Thanks :)
Gino Canessa (Aug 23 2019 at 18:23):
That said, the mechanism does support batched notifications. I believe the intent is that a server can make a determination (e.g., only send out notifications once every minute). We have discussed adding language to qualify/quantify the maximum time a server can take from an event to sending a notification, so that would play in here as well.
Jenni Syed (Aug 23 2019 at 18:26):
Yes, and that's discussed a bit on that other thread. The complication comes in when the server states "I'll batch every 5 min" and then 100 different client apps want their own intervals
Jenni Syed (Aug 23 2019 at 18:27):
It's not necessarily the server side that is the issue for this ask - it's mixing that to handle a number of unknown client intervals
Jenni Syed (Aug 23 2019 at 18:27):
(and noting that servers would likely batch in minute or sub, hopefully...)
dsh (Dec 23 2019 at 16:37):
How reliable is Subscription feature in Production use? FYI, I am planning to use JPA Starter server.
Will I be better just polling the server for a particular resource rather than relying on Subscription ??
Lloyd McKenzie (Dec 23 2019 at 17:11):
R4 subscription isn't that widely implemented. However, best to check with the partners you expect to interoperate with and see what their capabilities are
dsh (Dec 23 2019 at 17:22):
What response should be returned by subscriber upon successfully processing a subscription notification ?
Lloyd McKenzie (Dec 23 2019 at 18:04):
None.
Lloyd McKenzie (Dec 23 2019 at 18:05):
Depending on the subscription notification type, the server might eventually see a query retrieving the relevant resource, but there's no expectation a server would track that.
Last updated: Apr 12 2022 at 19:14 UTC
