Date: Wed, 13 Apr 2022 18:25:31 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Antonin Houska <ah@cybertec.at>, Stephen Frost <sfrost@snowman.net>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Temporary file access API
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On Mon, Apr 11, 2022 at 04:34:18PM -0400, Robert Haas wrote:
> On Mon, Apr 11, 2022 at 4:05 AM Antonin Houska <ah@cybertec.at> wrote:
> > There are't really that many kinds of files to encrypt:
> >
> > https://wiki.postgresql.org/wiki/Transparent_Data_Encryption#List_of_the_files_that_contain_user_data
> >
> > (And pg_stat/* files should be removed from the list.)
> 
> This kind of gets into some theoretical questions. Like, do we think
> that it's an information leak if people can look at how many
> transactions are committing and aborting in pg_xact_status? In theory
> it could be, but I know it's been argued that that's too much of a
> side channel. I'm not sure I believe that, but it's arguable.
> Similarly, the argument that global/pg_internal.init doesn't contain
> user data relies on the theory that the only table data that will make
> its way into the file is for system catalogs. I guess that's not user
> data *exactly* but ... are we sure that's how we want to roll here?

I don't think we want to be encrypting pg_xact/, so they can get the
transaction commit rate from there.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Indecision is a decision.  Inaction is an action.  Mark Batterson