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

Hello

Running it with format "directory" produced something I cannot import form the host application. So I aborted that.

Running it now and recording with Instruments. Guess I'll have to leave it cooking for the full procedure but I've added an initial one to pastebin.
https://pastebin.com/QHRYUQhb

I'm not sure if I can attach screenshots here. Trying, screenshot from instruments after running for a few mins.

[cid:096ABFB7-4DE0-4C82-BA26-7F14A846AEEA]

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Henrik Cednert
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On 21 Nov 2017, at 19:46, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us<mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us>> wrote:

Robert Haas <robertmhaas(at)gmail(dot)com<mailto: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<mailto: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