Uncertain about partial response propagation

[wiardvanrij]

I'm not sure if this is a bug or not, but I suspect it might be since I'm experiencing this issue.

To explain things better, I've made this 'diagram', which is actually a simplification of how our stack looks like.

To explain the setup:

• There is some chaining involved
• One querier chains to another querier, where that second querier access 'B' stores
• In reality, there is even more chaining involved, where we have this 'TLS' querier and one without, and we chain that into another querier - Yet I think for this question, it's not relevant.

My ask here is:

• If one of the B stores, let's say xB, is down. It should provide that querier with a partial response.
• Does this propagate correctly to the initial querier (on the left) as well?

Main reason I'm asking, is that I had this case were partial data was cached by the query frontend cache. Which simply can never happen because we have strict endpoints. Therefore I'm assuming there is a bug somewhere.