From 3d2e8573e9cb91bd2b545184f4f9b326d237bcd1 Mon Sep 17 00:00:00 2001
From: Daniel Gustafsson <dgustafsson@postgresql.org>
Date: Tue, 15 Sep 2026 13:46:52 +0200
Subject: [PATCH] doc:  Database and tablespace size functions throws error

Commit b6463ea6ef3e46 added an explicit ereport on missing object
to pg_database_size and pg_tablespace_size, but the documentation
wasn't updated to match.

Author: Zhong ShiHao <zhong950419@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: solai v <solai.cdac@gmail.com>
Discussion: https://postgr.es/m/CAGRkXqQSegqDnkRf344G=80mJMn78o9u=auHnx=u1jf=XpuE0A@mail.gmail.com
Backpatch-through: 18
---
 doc/src/sgml/func.sgml | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index b57f161f53c..d065b8be1e1 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -30043,7 +30043,9 @@ postgres=# SELECT '0/0'::pg_lsn + pd.segment_number * ps.setting::int + :offset
     or understanding of usage results.  <literal>bigint</literal> results
     are measured in bytes.  If an OID that does
     not represent an existing object is passed to one of these
-    functions, <literal>NULL</literal> is returned.
+    functions, <literal>NULL</literal> is returned, except for
+    <function>pg_database_size</function> and
+    <function>pg_tablespace_size</function>, which raise an error.
    </para>
 
    <table id="functions-admin-dbsize">
@@ -30125,7 +30127,8 @@ postgres=# SELECT '0/0'::pg_lsn + pd.segment_number * ps.setting::int + :offset
         name or OID.  To use this function, you must
         have <literal>CONNECT</literal> privilege on the specified database
         (which is granted by default) or have privileges of
-        the <literal>pg_read_all_stats</literal> role.
+        the <literal>pg_read_all_stats</literal> role.  Throws an error if the
+        database does not exist.
        </para></entry>
       </row>
 
@@ -30258,7 +30261,8 @@ postgres=# SELECT '0/0'::pg_lsn + pd.segment_number * ps.setting::int + :offset
         specified name or OID. To use this function, you must
         have <literal>CREATE</literal> privilege on the specified tablespace
         or have privileges of the <literal>pg_read_all_stats</literal> role,
-        unless it is the default tablespace for the current database.
+        unless it is the default tablespace for the current database. Throws
+        an error if the tablespace does not exist.
        </para></entry>
       </row>