Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade

"Henrik Cednert (Filmlance)" <henrik.cednert@filmlance.se> writes:
> The last pg_dump with 8.4 took 212 minutes and 49 seconds.And now with 9.5 the very same pg_dump takes 644 minutes
and40 seconds. To it takes about three times as long now and I have no idea to why. Nothing in the system or hardware
otherthan the pgsql upgrade have change. 

Can you get a profile of where the machine is spending its time during the
dump run?  On Linux I'd recommend "perf", but on macOS, hmm ...
You could use Activity Monitor, but as far as I can see that just captures
short-duration snapshots, which might not be representative of a 10-hour
run.  XCode's Instruments feature would probably be better about giving
a full picture, but it has a steep learning curve.
        regards, tom lane