From 4f08ab55457751308ffd8d33e82155758cd0e304 Mon Sep 17 00:00:00 2001
From: Fujii Masao <fujii@postgresql.org>
Date: Wed, 18 Sep 2024 12:51:48 +0900
Subject: postgres_fdw: Extend postgres_fdw_get_connections to return user
 name.

This commit adds a "user_name" output column to
the postgres_fdw_get_connections function, returning the name
of the local user mapped to the foreign server for each connection.
If a public mapping is used, it returns "public."

This helps identify postgres_fdw connections more easily,
such as determining which connections are invalid, closed,
or used within the current transaction.

No extension version bump is needed, as commit c297a47c5f
already handled it for v18~.

Author: Hayato Kuroda
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/b492a935-6c7e-8c08-e485-3c1d64d7d10f@oss.nttdata.com
---
 doc/src/sgml/postgres-fdw.sgml | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

(limited to 'doc/src')

diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index 468724e94ef..627bb5ab5cc 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -779,7 +779,8 @@ OPTIONS (ADD password_required 'false');
    <varlistentry>
     <term><function>postgres_fdw_get_connections(
       IN check_conn boolean DEFAULT false, OUT server_name text,
-      OUT valid boolean, OUT used_in_xact boolean, OUT closed boolean)
+      OUT user_name text, OUT valid boolean, OUT used_in_xact boolean,
+      OUT closed boolean)
       returns setof record</function></term>
     <listitem>
      <para>
@@ -806,10 +807,12 @@ OPTIONS (ADD password_required 'false');
      <para>
       Example usage of the function:
 <screen>
- server_name | valid | used_in_xact | closed
--------------+-------+--------------+--------
- loopback1   | t     | t            |
- loopback2   | f     | t            |
+postgres=# SELECT * FROM postgres_fdw_get_connections(true);
+ server_name | user_name | valid | used_in_xact | closed
+-------------+-----------+-------+--------------+--------
+ loopback1   | postgres  | t     | t            | f
+ loopback2   | public    | t     | t            | f
+ loopback3   |           | f     | t            | f
 </screen>
       The output columns are described in
       <xref linkend="postgres-fdw-get-connections-columns"/>.
@@ -836,6 +839,16 @@ OPTIONS (ADD password_required 'false');
          invalid), this will be <literal>NULL</literal>.
         </entry>
        </row>
+       <row>
+        <entry><structfield>user_name</structfield></entry>
+        <entry><type>text</type></entry>
+        <entry>
+         Name of the local user mapped to the foreign server of this
+         connection, or <literal>public</literal> if a public mapping is used.
+         If the user mapping is dropped but the connection remains open
+         (i.e., marked as invalid), this will be <literal>NULL</literal>.
+        </entry>
+       </row>
        <row>
         <entry><structfield>valid</structfield></entry>
         <entry><type>boolean</type></entry>
-- 
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