From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Henrik Cednert (Filmlance)" <henrik.cednert@filmlance.se>
cc: "pgsql-performance@lists.postgresql.org"
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Subject: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade
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Comments: In-reply-to "Henrik Cednert (Filmlance)"
 <henrik.cednert@filmlance.se>
	message dated "Tue, 21 Nov 2017 18:53:29 +0000"
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Date: Tue, 21 Nov 2017 16:01:20 -0500
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"Henrik Cednert (Filmlance)" <henrik.cednert@filmlance.se> writes:
> I'm not sure if I can attach screenshots here. Trying, screenshot from i=
nstruments after running for a few mins.

It looks like practically all of pg_dump's time is going into deflate(),
ie zlib.  I don't find that terribly surprising in itself, but it offers
no explanation for why you'd see a slowdown --- zlib isn't even our
code, nor has it been under active development for a long time, so
presumably 8.4 and 9.5 would have used the same version.  Perhaps you
were doing the 8.4 dump without compression enabled?

			regards, tom lane