Stream: cql
Topic: CQF Ruler CQL to FHIR Query
Andy Stevens (Nov 10 2021 at 21:19):
An issue we ran into using CQF Ruler is that we kept getting stream timeouts while trying to run some CQL against a FHIR server (about 7 retrieve statements). We ended up running it against a basic (almost) empty HAPI FHIR server and looked at the logs to see what kind of FHIR queries CQF Ruler was making.
We found out that having CQL in the form of [Observation: code in "concepts"] would make a FHIR query of an Observation with only the search parameter of subject=Patient.id, so it was returning all Observations for the patient, and when using against a server where a patient has 27,000 Observations, it causes a timeout.
However, I then changed the CQL retrieve to [Observation: "concepts"] and the HAPI FHIR logs showed a FHIR query of an Observation with subject=Patient.id and code=all of the codes in the defined concept set, so that does the correct kind of query
Is this an issue with how the ruler evaluates different cql syntax, or is there something else that we're missing here?
Bryn Rhodes (Nov 10 2021 at 23:14):
That is interesting that you are seeing different query behavior there, I just verified that the ELM output for those two is the same (assuming "concepts" is a reference to a value set?)
Bryn Rhodes (Nov 10 2021 at 23:15):
I will dig in and see if I can tell what's going on
Michael Riley (Nov 11 2021 at 15:49):
Bryn, is there an elm datastructure (trace?) we could send to help you investigate?
Last updated: Apr 12 2022 at 19:14 UTC
