And another question, @filiphr: there is this parameter called asyncExecutorDefaultQueueSizeFullWaitTime that is described as follows:
The time (in milliseconds) the async job (both timer and async continuations) acquisition thread will wait when the internal job queue is full to execute the next query. By default set to 0 (for backwards compatibility). Setting this property to a higher value allows the async executor to hopefully clear its queue a bit.
Does it help, in general, to speed things up if I set it to a non-zero value, e.g. 10000 (10 seconds)?