upstream/postgresql
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2026-04-22 06:37:06 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

psql: Add %i prompt escape to indicate hot standby status.

Browse source 
This commit introduces a new prompt escape %i for psql, which shows
whether the connected server is operating in hot standby mode. It
expands to standby if the server reports in_hot_standby = on, and
primary otherwise.

This is useful for distinguishing standby servers from primary ones
at a glance, especially when working with multiple connections in
replicated environments where libpq's multi-host connection strings
are used.

Author: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Greg Sabino Mullane <htamfids@gmail.com>
Reviewed-by: Srinath Reddy Sadipiralla <srinath2133@gmail.com>
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Discussion: https://www.postgresql.org/message-id/flat/016f6738-f9a9-4e98-bb5a-e1e4b9591d46@uni-muenster.de
This commit is contained in:
Fujii Masao 2026-02-03 10:03:19 +09:00
parent 4a99ef1a0d
commit dddbbc253b
2 changed files with 35 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

17
doc/src/sgml/ref/psql-ref.sgml
View file

@ -5075,6 +5075,23 @@ testdb=&gt; <userinput>INSERT INTO my_table VALUES (:'content');</userinput>
</listitem>
</varlistentry>
<varlistentry id="app-psql-prompting-i">
<term><literal>%i</literal></term>
<listitem>
<para>
Indicates whether the connected server is running in hot standby mode.
The value is shown as <literal>standby</literal>, if the server is
currently in hot standby and reports
<xref linkend="guc-in-hot-standby"/> as <literal>on</literal>,
and <literal>primary</literal> otherwise. This is useful when
connecting to multiple servers to quickly determine the role of
each connection. A value of <literal>?</literal> is shown
when connected to a server running
<productname>PostgreSQL</productname> 13 or older.
</para>
</listitem>
</varlistentry>
<varlistentry id="app-psql-prompting-x">
<term><literal>%x</literal></term>
<listitem>

18
src/bin/psql/prompt.c
View file

@ -44,6 +44,8 @@
* or a ! if session is not connected to a database;
* in prompt2 -, *, ', or ";
* in prompt3 nothing
* %i - "standby" or "primary" depending on the server's in_hot_standby
* status, or "?" if unavailable (empty if unknown)
* %x - transaction status: empty, *, !, ? (unknown or no connection)
* %l - The line number inside the current statement, starting from 1.
* %? - the error code of the last query (not yet implemented)
@ -258,7 +260,23 @@ get_prompt(promptStatus_t status, ConditionalStack cstack)
break;
}
break;
case 'i':
if (pset.db)
{
const char *hs = PQparameterStatus(pset.db, "in_hot_standby");
if (hs)
{
if (strcmp(hs, "on") == 0)
strlcpy(buf, "standby", sizeof(buf));
else
strlcpy(buf, "primary", sizeof(buf));
}
/* Use ? for versions that don't report in_hot_standby */
else
buf[0] = '?';
}
break;
case 'x':
if (!pset.db)
buf[0] = '?';