The HAPI FHIR JPA Server fully implements most FHIR search operations for most versions of FHIR. However, there are some known limitations of the current implementation. Here is a partial list of search functionality that is not currently supported in HAPI FHIR:
Searching by date with no timestamp currently doesn't match all records it should. See Issue 1499.
Chains within _has are not currently supported for performance reasons. For example, this search is not currently supported
https://localhost:8000/Practitioner?_has:PractitionerRole:practitioner:service.type=CHIRO
Searching on Location.Position using near currently uses a box search, not a radius search. A box search is a square centred on the provided coordinates with the shortest distance to the edge of the square equal to the distance provided; this means the box search will match more locations than a radius search in the corners. Currently, distance is assumed to be in km and any provided units are ignored. Distance must be between 0.0km and 10,000km.
The special _filter is only partially implemented.