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Subject: Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade
From: Matthew Hall <mhall@mhcomputing.net>
In-Reply-To: <12D87F70-956E-499B-9532-DAC52F419837@filmlance.se>
Date: Wed, 22 Nov 2017 11:52:11 -0800
Cc: "pgsql-performance@lists.postgresql.org"
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To: "Henrik Cednert (Filmlance)" <henrik.cednert@filmlance.se>
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On Nov 22, 2017, at 5:06 AM, Henrik Cednert (Filmlance) =
<henrik.cednert@filmlance.se> wrote:
>=20
> When investigating the zlib lead I looked at 8.4 installation and 9.5 =
installation. 9.5 includes zlib.h =
(/Library/PostgreSQL//9.5/include/zlib.h), but 8.4 doesn't. But that's a =
header file and I have no idea how that really works and if that's the =
one used by pgres9.5 or not. The version in it says 1.2.8 and that's =
what the Instruments are showing when I monitor pg_dump while running.=20=

>=20
> Guess I'll have to install instruments in a dev env and do a pg_dump =
with 8.4 to see the difference. Tedious. =3D/=20

I would also check the library linkages of the pg_dump binaries.

See if one thing is using an embedded zlib and the other a system zlib.

Then you could imagine one didn't get compiled with the best-performing =
CFLAGS, etc.

Matthew.=