From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Henrik Cednert (Filmlance) <henrik.cednert@filmlance.se>
Cc: pgsql-performance@lists.postgresql.org <pgsql-performance@lists.postgresql.org>
Subject: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade
Date: Tue, 21 Nov 2017 13:46:09 -0500
Message-ID: <14231.1511289969@sss.pgh.pa.us> (raw)
In-Reply-To: <CA+TgmoY3F+Yiheh-41wuLVzozw9sKQFqBG2fqSbskKvL20tFrw@mail.gmail.com>
References: <8F33D0C7-E12E-4996-990C-3CF0C5ED0437@filmlance.se>
<7442.1511283687@sss.pgh.pa.us>
<CA+TgmoY3F+Yiheh-41wuLVzozw9sKQFqBG2fqSbskKvL20tFrw@mail.gmail.com>
Robert Haas <robertmhaas@gmail.com> writes:
> On Tue, Nov 21, 2017 at 12:01 PM, Tom Lane <tgl@sss.pgh.pa.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
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Cc: tgl@sss.pgh.pa.us, robertmhaas@gmail.com, henrik.cednert@filmlance.se, pgsql-performance@lists.postgresql.org
Subject: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade
In-Reply-To: <14231.1511289969@sss.pgh.pa.us>
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