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Date: Fri, 25 Jul 2025 00:44:01 +0200
From: "Pierre Barre" <pierre@barre.sh>
To: "Jeff Ross" <jross@openvistas.net>, pgsql-general@lists.postgresql.org
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Subject: Re: PostgreSQL on S3-backed Block Storage with Near-Local Performance
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> This then begs the obvious question of how fast is this with=20
> synchronous_commit =3D on?

Probably not awful, especially with commit_delay.

I'll try that and report back.

Best,
Pierre

On Fri, Jul 25, 2025, at 00:03, Jeff Ross wrote:
> On 7/24/25 13:50, Pierre Barre wrote:
>
>> It=E2=80=99s not =E2=80=9Csafe=E2=80=9D or =E2=80=9Cunsafe=E2=80=9D, =
there=E2=80=99s mountains of valid workloads which don=E2=80=99t require=
 synchronous_commit. Synchronous_commit don=E2=80=99t make your system a=
utomatically safe either, and if that=E2=80=99s a requirement, there=E2=80=
=99s many workarounds, as you suggested, it certainly doesn=E2=80=99t ma=
ke the setup useless.
>>
>> Best,
>> Pierre
>>
>> On Thu, Jul 24, 2025, at 21:44, Nico Williams wrote:
>>> On Fri, Jul 18, 2025 at 12:57:39PM +0200, Pierre Barre wrote:
>>>> - Postgres configured accordingly memory-wise as well as with
>>>>    synchronous_commit =3D off, wal_init_zero =3D off and wal_recycl=
e =3D off.
>>> Bingo.  That's why it's fast (synchronous_commit =3D off).  It's als=
o why
>>> it's not safe _unless_ you have a local, fast, persistent ZIL device
>>> (which I assume you don't).
>>>
>>> Nico
>>> --
> This then begs the obvious question of how fast is this with=20
> synchronous_commit =3D on?