"Henrik Cednert (Filmlance)" <henrik.cedn...@filmlance.se> writes:
> I'm not sure if I can attach screenshots here. Trying, screenshot from
> instruments after running for a few mins.
It looks like practically all of pg_dump's time is going into deflate(),
ie zlib. I don't find that terribly surprising in itself, but it offers
no explanation for why you'd see a slowdown --- zlib isn't even our
code, nor has it been under active development for a long time, so
presumably 8.4 and 9.5 would have used the same version. Perhaps you
were doing the 8.4 dump without compression enabled?
regards, tom lane