> Is Pebble/CockroachDB capable of saturating the backplane with requests in parallel?
Yes.
> Does it multiplex a single query by dispatching smaller requests to a thread-pool?
Yes, though it depends on the query. Trivial queries (i.e. single-row lookups) are executed serially as that is the fastest way to execute them. Complex queries are decomposed along data boundaries and the query parts are executed in parallel next to where the data is located.
Yes.
> Does it multiplex a single query by dispatching smaller requests to a thread-pool?
Yes, though it depends on the query. Trivial queries (i.e. single-row lookups) are executed serially as that is the fastest way to execute them. Complex queries are decomposed along data boundaries and the query parts are executed in parallel next to where the data is located.