> Curious: would it be both feasible and useful to have multiple > workers process a 'large' table, without complicating things too > much? The could each start at a different position in the file.
Feasible: no. Useful: maybe, we don't really know. (You could just as well have a worker at double the speed, i.e. double vacuum_cost_limit).
Vacuum_cost_delay is already 0 by default. So unless you changed that, vacuum_cost_limit does not take effect under vacuumdb.
It is pretty easy for vacuum to be CPU limited, and even easier for analyze to be CPU limited (It does a lot of sorting). I think analyzing is the main use case for this patch, to shorten the pg_upgrade window. At least, that is how I anticipate using it.
