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From: Jacob Biesinger <jake.biesinger@gmail.com>
Date: Wed, 16 Oct 2024 12:28:04 -0700
Message-ID: <CAHYXj6f0X4CU+xzTZRHmA_0b+99CnLUHu8fabbPVW4XL1qw0yQ@mail.gmail.com>
Subject: Re: serializable master and non-serializable hot standby: feasible
 set up?
To: Laurenz Albe <laurenz.albe@cybertec.at>
Cc: pgsql-general@lists.postgresql.org
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On Tue, Oct 15, 2024 at 9:23=E2=80=AFPM Laurenz Albe <laurenz.albe@cybertec=
.at>
wrote:

> On Tue, 2024-10-15 at 16:27 -0700, Jacob Biesinger wrote:
> > *would you* expect to be able to stand up a `repeatable read` replica
> against a
> > `serializable` master? My expectation is that you'd simply change the
> setting in
> > a .conf file on the replica and be good to go; is there something that
> would make
> > this process really difficult / impossible?
>
> I expect that to work fine, at least I cannot think of a problem with suc=
h
> a setup.
> But I have been wrong before, so test it.
>

The setup (serializable master, repeatable read replica) definitely works
-- we've been running that way for over a year now. I guess I'm really
asking "how would you go about getting the replica into the appropriate
state?" Would you expect to have to downgrade the master's isolation level
as I describe? Or would you expect to be able to stand up the replica using
a modified conf file initially?

Thanks as always for your help!

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<div dir=3D"ltr"><div dir=3D"ltr">On Tue, Oct 15, 2024 at 9:23=E2=80=AFPM L=
aurenz Albe &lt;<a href=3D"mailto:laurenz.albe@cybertec.at">laurenz.albe@cy=
bertec.at</a>&gt; wrote:<br></div><div class=3D"gmail_quote"><blockquote cl=
ass=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid=
 rgb(204,204,204);padding-left:1ex">On Tue, 2024-10-15 at 16:27 -0700, Jaco=
b Biesinger wrote:<br>
&gt; *would you* expect to be able to stand up a `repeatable read` replica =
against a<br>
&gt; `serializable` master? My expectation is that you&#39;d simply change =
the setting in<br>
&gt; a .conf file on the replica and be good to go; is there something that=
 would make<br>
&gt; this process really difficult / impossible?<br>
<br>
I expect that to work fine, at least I cannot think of a problem with such =
a setup.<br>
But I have been wrong before, so test it.<br></blockquote><div><br></div><d=
iv>The setup (serializable master, repeatable read replica) definitely work=
s -- we&#39;ve been running that way for over a year now. I guess I&#39;m r=
eally asking &quot;how would you go about getting the replica into the appr=
opriate state?&quot; Would you expect to have to downgrade the master&#39;s=
 isolation level as I describe? Or would you expect to be able to stand up =
the replica using a modified conf file initially?</div><div>=C2=A0</div><di=
v>Thanks as always for your help!</div></div></div>

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