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

From: Tom Lane
Subject: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade
Date: ,
Msg-id: 14231.1511289969@sss.pgh.pa.us
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In response to: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Robert Haas)
Responses: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)")
Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)")
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pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
 RE: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Igor Neyman, )
  Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
   RE: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Igor Neyman, )
    Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
     RE: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Igor Neyman, )
      Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
       RE: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Igor Neyman, )
  Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Shaul Dar, )
 Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Tom Lane, )
  Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Robert Haas, )
   Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Tom Lane, )
    Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
     Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Tom Lane, )
      Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
       Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
        Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Matthew Hall, )
         Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
          Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
           Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Matthew Hall, )
            Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
         Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Andres Freund, )
    Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
 Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Patrick KUI-LI, )
  Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  ("Henrik Cednert (Filmlance)", )
   Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Gunther, )
    Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Laurenz Albe, )
     Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade  (Claudio Freire, )

Robert Haas <> writes:
> On Tue, Nov 21, 2017 at 12:01 PM, Tom Lane <> 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



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From: Tom Lane
Date:
Subject: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade
From: "Henrik Cednert (Filmlance)"
Date:
Subject: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade