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From: Ron Johnson <ronljohnsonjr@gmail.com>
Date: Wed, 12 Nov 2025 11:11:56 -0500
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Subject: Re: pg_dump -j
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On Wed, Nov 12, 2025 at 10:34=E2=80=AFAM Sam Stearns <sam.stearns@dat.com> =
wrote:

> Howdy,
>
> Would someone be able to advise on the correct setting for the -j option
> of pg_dump to run the dump in parallel, please?  Is it based on CPU count=
,
> or something else?  The output of nproc is 32.
>

I'd certainly never go *beyond* $(nproc), but since COPY generates a lot of
IO and compression burns through CPU, it all depends on the system's other
workload.  Only you know what your system's other workload is when pg_dump
is running.

--=20
Death to <Redacted>, and butter sauce.
Don't boil me, I'm still alive.
<Redacted> lobster!

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<div dir=3D"ltr"><div dir=3D"ltr">On Wed, Nov 12, 2025 at 10:34=E2=80=AFAM =
Sam Stearns &lt;<a href=3D"mailto:sam.stearns@dat.com">sam.stearns@dat.com<=
/a>&gt; wrote:</div><div class=3D"gmail_quote gmail_quote_container"><block=
quote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1=
px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr"><div>Howdy,</d=
iv><div><br></div><div>Would someone be able to advise on the correct setti=
ng for the -j option of pg_dump to run the dump in parallel, please?=C2=A0 =
Is it based on CPU count, or something else?=C2=A0 The output of nproc is 3=
2.</div></div></blockquote><div></div></div><div><br></div><div>I&#39;d cer=
tainly never go <i>beyond</i>=C2=A0$(nproc), but since COPY generates a lot=
 of IO and compression burns through CPU, it all depends on the system&#39;=
s other workload.=C2=A0 Only you know what your system&#39;s other workload=
 is when pg_dump is running.</div><div><br></div><span class=3D"gmail_signa=
ture_prefix">-- </span><br><div dir=3D"ltr" class=3D"gmail_signature"><div =
dir=3D"ltr">Death to &lt;Redacted&gt;, and butter sauce.<div>Don&#39;t boil=
 me, I&#39;m still alive.<br><div><div>&lt;Redacted&gt; lobster!</div></div=
></div></div></div></div>

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