public inbox for [email protected]  
help / color / mirror / Atom feed
From: Merlin Moncure <[email protected]>
To: Laurenz Albe <[email protected]>
Cc: Ashish Mukherjee <[email protected]>
Cc: [email protected]
Subject: Re: Downgrade pgsql 17 to pgsql 12 question
Date: Tue, 30 Sep 2025 09:13:06 -0600
Message-ID: <CAHyXU0ynctRCs73d6tk-=jMgfE1jrz=KK5LurvrGmMUHPQPDTw@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <CACgMzfxO7h+Bj4T8rjTV=trM3+Uw=jOAcUE+0Kimv4DSAVU1JA@mail.gmail.com>
	<CAHyXU0ynqbCHrw3XvofEzidHow4tx1FFGNB2FUR5-wj-EhLcNQ@mail.gmail.com>
	<CACgMzfwyMxq+qVFBMXzsMFFdBKJ5aRf_REX01KHL1mcVpRKwyA@mail.gmail.com>
	<[email protected]>

On Tue, Sep 30, 2025 at 3:47 AM Laurenz Albe <[email protected]>
wrote:

> On Tue, 2025-09-30 at 13:53 +0530, Ashish Mukherjee wrote:
> > 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).
>
> I will refrain from making a recommendation, but you should know that
> data-at-rest encryption will always incur a certain performance penalty.
>
> Whatever solution you choose, you should run performance tests.
>

Yeah.  This applies to database upgrades in general.

The lists have quite a bit of, I upgraded, and "query X that drives my
platform now is 100x slower".  I don't think this suggests that postgres is
getting worse; foundationally, it's mostly getting faster, but simply that
the planner changes how it responds to certain conditions.  Over time, I've
learned some painful lessons and try to write SQL that is less risky from a
performance standpoint.

Developers tend to optimize into fragile planner behaviors chasing
performance, sometimes without realizing it.  These kinds of issues are
almost always very fixable assuming you can modify the SQL or the thing
writing the SQL. The takeaway here is: test/verify before making major
upgrades, and bake in some recalibration time.  Adding encryption or other
major features strongly reinforces that need.

merlin


view thread (9+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected]
  Subject: Re: Downgrade pgsql 17 to pgsql 12 question
  In-Reply-To: <CAHyXU0ynctRCs73d6tk-=jMgfE1jrz=KK5LurvrGmMUHPQPDTw@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox