Description

We dedicate a fair amount of time and code complexity to supporting multi-ZID wikilambda_fetch queries, but we never actually make multi-ZID queries in the orchestrator. We should either commit to using that API or vastly simplify our code.

Desired behavior/Acceptance criteria (returned value, expected error, performance expectations, etc.)

• decide which to do
• do it

Completion checklist

• Before closing this task, review one by one the checklist available here: https://www.mediawiki.org/wiki/Abstract_Wikipedia_team/Definition_of_Done#Back-end_Task/Bug_completion_checklist