Re: Review: Revise parallel pg_restore's scheduling heuristic

"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> Over the weekend I ran 40 restores of Milwaukee County's production
> data using Friday's snapshot with and without the patch. I alternated
> between patched and unpatched. It appears that this latest version is
> slightly slower for our production database on the same machine and
> configuration where the previous patch appeared to be 1% to 2% faster
> than unpatched (although I had fewer samples of that).

I think we can conclude that for this particular test case, the effects
of the patch are pretty much masked by noise. I definitely see no way
that the latest version of the patch could really be slower than the
original; it has the same job-scheduling behavior and strictly less
list-munging overhead. Now the patch could be slower than unpatched
as a result of different job-scheduling behavior ... but there's no
evidence here of a consistently measurable benefit or loss from that.

IIRC daveg was volunteering to do some tests with his own data; maybe
we should wait for those results.

regards, tom lane