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From: Alicja Kucharczyk <zaledwie10minut@gmail.com>
Date: Thu, 29 Jan 2026 15:57:47 +0100
Message-ID: 
 <CAM=sWa5auURVFGJZ-wL9NS5vpV2AdN=mJBo6G4ZjXuE+cCGFfw@mail.gmail.com>
Subject: Re: Setting huge_pages=off when HugePages are allocated in Linux?
To: =?UTF-8?Q?Roland_M=C3=BCller?= <rolmur@gmail.com>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>,
 Ron Johnson <ronljohnsonjr@gmail.com>,
	Pgsql-admin <pgsql-admin@lists.postgresql.org>
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> When does it make sense to use hugepages in Postgresql?
>
Usually when your shared memory footprint is very large, i.e. primarily
very large shared_buffers. In practice, huge pages tend to pay off on
dedicated, high-throughput systems where shared_buffers is really big
(often tens of GB, and very commonly you start caring around ~100GB+) and
you have high concurrency / tight latency goals.


> Is usage of hugepages only available in release 18?
>
No, huge pages support has been around since PostgreSQL 9.4. But starting
with PostgreSQL 15, it=E2=80=99s much easier to size/configure because Post=
greSQL
can tell you the required count via the runtime-computed setting
shared_memory_size_in_huge_pages, before that you needed to calculate it on
your own.

regards,
A.Kucharczyk

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><div class=3D"gmail_quote gmail=
_quote_container"><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px=
 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div di=
r=3D"auto">When does it make sense to use hugepages in Postgresql?=C2=A0</d=
iv></blockquote><div>Usually when your shared memory footprint is very larg=
e, i.e. primarily very large shared_buffers. In practice, huge pages tend t=
o pay off on dedicated, high-throughput systems where shared_buffers is rea=
lly big (often tens of GB, and very commonly you start caring around ~100GB=
+) and you have high concurrency / tight latency goals.</div><div>=C2=A0</d=
iv><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;bord=
er-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"auto"><div=
 dir=3D"auto">Is usage of hugepages only available in release 18?</div></di=
v></blockquote><div>No, huge pages support has been around since PostgreSQL=
 9.4. But=C2=A0starting with PostgreSQL 15, it=E2=80=99s much easier to siz=
e/configure because PostgreSQL can tell you the required count via the runt=
ime-computed setting shared_memory_size_in_huge_pages, before that you need=
ed to calculate it on your own.</div><div>=C2=A0</div><div>regards,</div><d=
iv>A.Kucharczyk=C2=A0</div></div></div>

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