Date: Wed, 22 Jul 2026 15:12:26 +0200
From: Christoph Berg <myon@debian.org>
To: Fujii Masao <masao.fujii@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
	Zsolt Parragi <zsolt.parragi@percona.com>
Subject: Re: Allow pg_read_all_stats to see database size in \l+
Message-ID: <amDBusAY5ysRg-LQ@msg.df7cb.de>
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Thanks for the review!

Re: Fujii Masao
> The pg_read_all_stats check should be fine in master, since psql there
> no longer supports pre-v10 servers, which don't have that role. But,
> if this is backpatched, psql still needs to work with pre-v10 servers,
> so we'll probably need a server version check (e.g., pset.sversion >= 100000)
> before checking for pg_read_all_stats, at least in the older stable branches.

The SQL-generating code there is already quite complex, and since no
one complained, perhaps just skip the backpatching if it's complicated.

I tried the patch back to version 9.3 and the query still works even
when the role doesn't exist there. (9.2 and earlier failed due to the
protocol version grease.)

> Also, should the following description of the \l+ meta-command in
> the psql docs be updated?
> 
>     (Size information is only available for databases that the current
> user can connect to.)

Done in v2.

Christoph

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From 5fe2f0e6bb07fa6fe2172d732c1be50b4698210d Mon Sep 17 00:00:00 2001
From: Christoph Berg <myon@debian.org>
Date: Wed, 22 Jul 2026 13:16:16 +0200
Subject: [PATCH v2] Allow pg_read_all_stats to see database size in \l+

The server already allows members of pg_read_all_stats to see the size
of all databases, but psql's \l+ was too restrictive.
---
 doc/src/sgml/ref/psql-ref.sgml | 5 +++--
 src/bin/psql/describe.c        | 3 ++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 56c2692e618..4d5ee11ddd9 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -2817,8 +2817,9 @@ SELECT
         are displayed in expanded mode.
         If <literal>+</literal> is appended to the command name, database
         sizes, default tablespaces, and descriptions are also displayed.
-        (Size information is only available for databases that the current
-        user can connect to.)
+        Except for superusers or roles with privileges of the
+        <literal>pg_read_all_stats</literal> role, size information is only
+        available for databases that the current user can connect to.
         </para>
         </listitem>
       </varlistentry>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index a2f09c26369..ad9c8affb4f 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -986,7 +986,8 @@ listAllDbs(const char *pattern, bool verbose)
 	printACLColumn(&buf, "d.datacl");
 	if (verbose)
 		appendPQExpBuffer(&buf,
-						  ",\n  CASE WHEN pg_catalog.has_database_privilege(d.datname, 'CONNECT')\n"
+						  ",\n  CASE WHEN pg_catalog.has_database_privilege(d.datname, 'CONNECT') OR\n"
+						  "               pg_catalog.pg_has_role('pg_read_all_stats', 'USAGE')\n"
 						  "       THEN pg_catalog.pg_size_pretty(pg_catalog.pg_database_size(d.datname))\n"
 						  "       ELSE 'No Access'\n"
 						  "  END as \"%s\""
-- 
2.53.0


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