Having reading the detailed explanations, I have to be honest they need some work, especially the one for
Both queries perform a sharding filter before the document fetch
Unfortunately I can’t say anything more, since it would tend to give the game away, however the 2nd paragraph of the answer for query 2, needs work.
I read the detail answers for extra insight, but that one left me scratch my head.
@NMullins I found those a bit confusing myself. I think there was an important detail left out concerning the precedence of certain bits…
Basically, SHARDING FILTER is a stage which filters result documents that are not owned by the current shard. And that is done by comparing the shard key of the document with the metadata of the config server.
And Thanks for such a valuable feedback. I agree, we can explain it in a better way.