I tinkered with this a bit. I think the case to add indexes for "REST" API may be weaker than even *I* thought (and I thought it was weak / was mostly against it).
The reason is cus there are reasons beyond indexing why such API calls are slow, and adding indexes may not even help that much. For example the TI list endpoint lists TIs. TIs have a *lot* of information distributed across many tables. We always load all of it. Sometimes multiple queries to get it. That's just not going to be an efficient way to implement change data capture a.k.a. replication. I think the main responsibility of airflow is to be performant with regard to task execution broadly defined. Anything beyond that is sort of not relevant. And getting data out of the metastore for ancillary purposes is outside that line IMO. The range of possible queries etc are too varied to reasonably optimize for. So it's best left to the person wearing the "dba" hat at the organization. Users can also add endpoints via plugins that query the data more efficiently. That's my take in a nutshell I guess.
