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

On Tue, Nov 21, 2017 at 12:01 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> "Henrik Cednert (Filmlance)" <henrik(dot)cednert(at)filmlance(dot)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 and 40 seconds. To it takes about three times as long now and I have no idea to why. Nothing in the system or hardware other than 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.

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

--
Robert Haas
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