Nice vacuums

I have an idea for a change to the contributed module pg_autovacuum that
I would like to run by people. What I want to do is make sure that when
vacuum (or analyze) runs that it takes no time from actual transactions.
To this end I want to add an option (-n?) which runs nice(2) on the
process ID of the backend.

I realize that there will be a limitation that this can only work when
pg_autovacuum is running on the same host as the server. I plan to
handle that by ignoring the new option if the -h option (or equivalent
environment variable) is also set.

The big question I have is this. Is this strategy likely to improve my
transaction processing?

--
D'Arcy J.M. Cain <darcy(at)druid(dot)net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.