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From: Ashish Mukherjee <ashish.mukherjee@gmail.com>
Date: Tue, 30 Sep 2025 13:53:23 +0530
Message-ID: <CACgMzfwyMxq+qVFBMXzsMFFdBKJ5aRf_REX01KHL1mcVpRKwyA@mail.gmail.com>
Subject: Re: Downgrade pgsql 17 to pgsql 12 question
To: Merlin Moncure <mmoncure@gmail.com>
Cc: pgsql-general@postgresql.org
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Thank you all for your inputs.

Well, Percona TDE was leading to the queries being very inefficient / slow
after upgrading to pgsql 17. Explain analyze shows that query planning time
shoots up crazily. A decision was taken to go back to pgsql 12, which
worked out fine as there was no incompatibility. I restored from the binary
dump with the -j option, as our database is huge. I completely agree that
downgrade is not a good option but a pragmatic one under the circumstances.

Now the consideration is to use some other encryption option for the
database which will work fine on pgsql 17. Cybertec's technology is one
route, the other is EDB. I am happy to hear experiences of folks here with
pgsql encryption options for v17 on large databases (2.5T in our case).

On Mon, Sep 29, 2025 at 5:10=E2=80=AFAM Merlin Moncure <mmoncure@gmail.com>=
 wrote:

> On Fri, Sep 26, 2025 at 8:16=E2=80=AFAM Ashish Mukherjee <
> ashish.mukherjee@gmail.com> wrote:
>
>> Hello,
>>
>> I have a strange requirement to downgrade from pgsql 17 to pgsql 12. Thi=
s
>> is because we found in production certain incompatibilities between both
>> versions for our database. It should have been caught in testing but was
>> not.
>>
>
> Agree with others that snap downgrade is not necessarily a good choice
> here.  Either way, if I were in your shoes, I'd be loading a plain text
> dump, maybe with some light massaging to strip out some compatibility
> issues.
>
> Can you let us know what the hang up is?  Version upgrades these days are
> usually pretty painless except for some performance issues, unless you ha=
ve
> some unusual situations, for example, exotic extensions.
>
> merlin
>
>

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<div dir=3D"ltr">Thank you all for your inputs.<div><br></div><div>Well, Pe=
rcona TDE was leading to the queries being very inefficient / slow after up=
grading to pgsql 17. Explain analyze shows that query planning time shoots =
up crazily. A decision was taken to go back to pgsql 12, which worked out f=
ine as there was no incompatibility. I restored from the binary dump with t=
he -j option, as our database is huge. I completely agree that downgrade is=
 not a good option but a pragmatic one under the circumstances.=C2=A0</div>=
<div><br></div><div>Now the consideration is to use some other encryption o=
ption for the database which will work fine on pgsql 17. Cybertec&#39;s tec=
hnology is one route, the other is EDB. I am happy to hear experiences of f=
olks here with pgsql encryption options for v17 on large databases (2.5T in=
 our case).</div></div><br><div class=3D"gmail_quote gmail_quote_container"=
><div dir=3D"ltr" class=3D"gmail_attr">On Mon, Sep 29, 2025 at 5:10=E2=80=
=AFAM Merlin Moncure &lt;<a href=3D"mailto:mmoncure@gmail.com">mmoncure@gma=
il.com</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"m=
argin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left=
:1ex"><div dir=3D"ltr"><div dir=3D"ltr">On Fri, Sep 26, 2025 at 8:16=E2=80=
=AFAM Ashish Mukherjee &lt;<a href=3D"mailto:ashish.mukherjee@gmail.com" ta=
rget=3D"_blank">ashish.mukherjee@gmail.com</a>&gt; wrote:</div><div class=
=3D"gmail_quote"><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 dir=
=3D"ltr">Hello,<div><br></div><div>I have a strange requirement to downgrad=
e from pgsql 17 to pgsql 12. This is because we found in production certain=
 incompatibilities=C2=A0between both versions for our database. It should h=
ave been caught in testing but was not.<br></div></div></blockquote><div><b=
r></div><div>Agree with others that snap downgrade is not necessarily a goo=
d choice here.=C2=A0 Either way, if I were in your shoes, I&#39;d be loadin=
g a plain text dump, maybe with some light massaging to strip out some comp=
atibility issues.</div><div><br></div><div>Can you let us know what the han=
g up is?=C2=A0 Version upgrades these days are usually pretty painless exce=
pt for some performance issues, unless you have some unusual situations, fo=
r example, exotic extensions.=C2=A0</div><div><br></div><div>merlin</div><d=
iv><br></div></div></div>
</blockquote></div>

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