From: bertrand HARTWIG <hartwig.bertrand@gmail.com>
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Subject: Re: About asynchronous I/O
Date: Tue, 23 Jun 2026 14:19:14 +0200
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 <CANzqJaAKAzYaGfPFLzt4ZZDs6sE5KGWuMmGWQ1oQYeC-wzHk_A@mail.gmail.com>
Cc: Pgsql-admin <pgsql-admin@lists.postgresql.org>
To: Ron Johnson <ronljohnsonjr@gmail.com>
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Very usefull on SSD AND nvme ! (low latency on IOPs). But the higher the =
disk latency, the greater the gains you will notice.

On SSD i observed 200%

> Le 23 juin 2026 =C3=A0 14:02, Ron Johnson <ronljohnsonjr@gmail.com> a =
=C3=A9crit :
>=20
> On Tue, Jun 23, 2026 at 7:26=E2=80=AFAM bertrand HARTWIG =
<hartwig.bertrand@gmail.com <mailto:hartwig.bertrand@gmail.com>> wrote:
>> Hello,
>>=20
>> The size of the database is clearly not important.
>>=20
>> What matters are queries that are not already cached and that perform =
I/O.
>>=20
>> With async I/O, you can see I/O performance improvements of up to =
200%=E2=80=93300%. The higher the disk latency, the greater the gains =
you will notice.
>>=20
>=20
> So, not so useful on SSD/NVMe?
> =20
>> Regards,
>>=20
>> Bertrand
>>=20
>>=20
>>> Le 23 juin 2026 =C3=A0 09:55, ek ek <livadidrive@gmail.com =
<mailto:livadidrive@gmail.com>> a =C3=A9crit :
>>>=20
>>> Hello everyone,
>>> Are any of you running PostgreSQL 18 on production environments =
sized between 1 to 3TB? Does the 'asynchronous I/O (AIO) subsystem' =
deliver a significant performance increase? Also, has anyone had the =
opportunity to benchmark it against v17?
>>=20
>=20
>=20
>=20
> --
> Death to <Redacted>, and butter sauce.
> Don't boil me, I'm still alive.
> <Redacted> lobster!


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<html aria-label=3D"message body"><head><meta http-equiv=3D"content-type" =
content=3D"text/html; charset=3Dutf-8"></head><body =
style=3D"overflow-wrap: break-word; -webkit-nbsp-mode: space; =
line-break: after-white-space;">Very usefull on SSD AND nvme ! (low =
latency on IOPs). But the higher the disk latency, the greater the gains =
you will notice.<div><br></div><div>On SSD i observed 200%<br =
id=3D"lineBreakAtBeginningOfMessage"><div><br><blockquote =
type=3D"cite"><div>Le 23 juin 2026 =C3=A0 14:02, Ron Johnson =
&lt;ronljohnsonjr@gmail.com&gt; a =C3=A9crit :</div><br =
class=3D"Apple-interchange-newline"><div><div dir=3D"ltr"><div =
dir=3D"ltr"><span style=3D"background-color:transparent">On Tue, Jun 23, =
2026 at 7:26=E2=80=AFAM bertrand HARTWIG &lt;<a =
href=3D"mailto:hartwig.bertrand@gmail.com">hartwig.bertrand@gmail.com</a>&=
gt; wrote:</span></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><p>Hello,</p><p>The size of the =
database is clearly not important.</p><p>What matters are queries that =
are not already cached and that perform I/O.</p><p>With async I/O, you =
can see I/O performance improvements of up to 200%=E2=80=93300%. The =
higher the disk latency, the greater the gains you will =
notice.</p></div></blockquote><div><br></div><div>So, not so useful on =
SSD/NVMe?</div><div>&nbsp;</div><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><p>Regards,</p><p>Bertrand</p><div=
><div><br><blockquote type=3D"cite"><div>Le 23 juin 2026 =C3=A0 09:55, =
ek ek &lt;<a href=3D"mailto:livadidrive@gmail.com" =
target=3D"_blank">livadidrive@gmail.com</a>&gt; a =C3=A9crit =
:</div><br><div><div dir=3D"auto"><div dir=3D"auto">Hello =
everyone,</div><div dir=3D"auto">Are any of you running PostgreSQL 18 on =
production environments sized between 1 to 3TB? Does the 'asynchronous =
I/O (AIO) subsystem' deliver a significant performance increase? Also, =
has anyone had the opportunity to benchmark it against v17?</div></div>
</div></blockquote></div><br></div></div></blockquote></div><div><br =
clear=3D"all"></div><div><br></div><span =
class=3D"gmail_signature_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't boil me, I'm still =
alive.<br><div><div>&lt;Redacted&gt; =
lobster!</div></div></div></div></div></div>
</div></blockquote></div><br></div></body></html>=

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