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

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Nov 21, 2017 at 12:01 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> 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.

> macOS's "sample" is pretty easy to use and produces text format output
> that is easy to email.

Ah, good idea. But note that only traces one process, so you'd need to
first determine whether it's pg_dump or the backend that's eating most
of the CPU. Or sample both of them.

regards, tom lane