OSS -> Azure Health Data Fhir Service

[reubenelder]

Hi,

We currently host the OSS FHIR server in our own subscription within Azure. We are currently evaluating whether we can switch to the Azure Health Data Fhir Service but we have a few questions:

1. In our existing setup we modify some of the configuration parameters, such as the default count limit and bundle size. I can't see a way of doing this in the health fhir service, is this possible?
2. We currently use AFD in front of our fhir service. This works well but relies on the fact that we can add a custom domain to the app service so that the URLs returned in the FHIR responses match the AFD url (rather than the default app service url). I note that others have a problem with custom URLs using Application Gateway. Are there plans to allow for custom urls?
3. I note that the managed service only supports FHIR versions 3 and 4. We are not planning on using v5 anytime soon but it is concerning that support isn't available even though it was released a while back. What are the expected timeframes around new FHIR releases?

Thanks,
Reuben

AB#118212

[brendankowitz]

Hi @reubenelder, I can jump on a few points here.

1. Currently no, HDS has limits that we feel balance the best performance vs latency across most cases. We're always open to learning where this doesn't work, let me know what you're using here.
2. I'll need to discuss this one internally, there would be some dev cost in the security aspect of this.
3. I'll let @EXPEkesheth weigh in on this topic. We will continue to track the demand for R5, my current read is that there is some debate over the wide R4 support + R6 being a larger normative release vs the effort in moving through R5. While R5 does have its improvements and use-cases, the incentive for a major shift through R5 doesn't seem clear.

[EXPEkesheth]

@reubenelder - are your questions answered? If no response, the issue ticket will be closed in a week

[reubenelder]

thanks for the reply @brendankowitz (sorry I was away for Easter otherwise I would have replied quicker).

1. We set the FhirServer__CoreFeatures__MaxItemCountPerSearch to 2000 currently. I can't remember what the default is - what is it set to in HDS? The reason for this is that we primarily use the FHIR service for medication resources of which there are over 80000 in various forms. Vendors need to be able to retrieve subsets of these in reasonable batches. We also set the FhirServer__Bundle__EntryLimit as when we submit updates we want as many batched up in a transaction as possible. Currently we use batches of 500 however most are a lot smaller than this but some are bigger. We would have liked to always include everything in one update batch but performance wise this was an issue (also when we last tested a very large batch asp.net core rejected the size of the request).
2. Thanks - do you know how others get around this currently?
3. I don't think I was very clear on this - we won't be moving to R5 either but was more concerned about how long R6 support would take after R6 is released?

[EXPEkesheth]

@reubenelder

1. In the managed service, by default search parameter count is set to 1000 . For details, please see Search Result Parameters. For bundles, the default value is 500 resources per bundle.
2. We have customers update the url in the application gateway. We have similar ask in our backlog and OSS issue tracking the ask.
3. R6 is meant to be a normative release and we would likely start investigating with the release. Also note, the support for R6 in FHIR service will be driven by customer demand.

[reubenelder]

thank you @EXPEkesheth for your response. I'll monitor the url request, hopefully this can be added soon.

In terms of the default count of 1000. Is there any hope that this could be adjustable in the future?

[EXPEkesheth]

Have created workitem in the backlog for consideration. Thankyou !

[reubenelder]

Excellent - thanks for that