Alvaro Herrera <alvherre@commandprompt.com> writes:
> If we apply Heikki's idea of advancing OldestXmin, I think what we
> should do is grab the value from pgstats when vacuum starts, and each
> time we're going to advance OldestXmin, grab the value from pgstats
> again; accumulate the differences from the various pgstat grabs. At the
> end we send the accumulated differences as the new dead tuple count.
Considering that each of those values will be up to half a second old,
I can hardly think that this will accomplish anything except to
introduce a great deal of noise ...
regards, tom lane