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From: Maiquel Grassi <[email protected]>
To: Pavel Luzanov <[email protected]>
To: Nathan Bossart <[email protected]>
Cc: Erik Wienhold <[email protected]>
Cc: [email protected] <[email protected]>
Subject: RE: Psql meta-command conninfo+
Date: Fri, 9 Feb 2024 09:18:44 +0000
Message-ID: <CP8P284MB2496D0B0946A4C55D7F0825EEC4B2@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <[email protected]>
References: <CP8P284MB24965CB63DAC00FC0EA4A475EC462@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM>
	<20240206181919.GA3853632@nathanxps13>
	<aevq2dxmw2xm2rc3nh2wdcozunipco447mf4rpm7efvqvz4wk2@mo3zmf2ulbzu>
	<CP8P284MB2496B51FC5ED9BD6527D459DEC462@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM>
	<20240206210605.GA3903769@nathanxps13>
	<20240206211205.GA3903996@nathanxps13>
	<CP8P284MB24965479BA59DF5C2CC01CA0EC462@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM>
	<20240206215022.GA3452@nathanxps13>
	<CP8P284MB2496A17A9852265A0F363A6AEC452@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM>
	<[email protected]>
	<CP8P284MB24961361A9C1D32C28A7EC0EEC452@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM>
	<[email protected]>
	<CP4P284MB24830F5BF17FFA7F3D733142EC452@CP4P284MB2483.BRAP284.PROD.OUTLOOK.COM>
	<[email protected]>
	<CP8P284MB249652F5F0BE828C20A38348EC442@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM>
	<[email protected]>

Hi Pavel!

>The patch v10 build ends with a warning:
>$ make -j --silent
>describe.c:911:1: warning: no previous prototype for ‘listConnectionInformation’ [-Wmissing-prototypes]
>  911 | listConnectionInformation()
      | ^~~~~~~~~~~~~~~~~~~~~~~~~

>About terms.

I resolved this in v11. I had forgotten to put
the 'void' inside the parentheses (describe.h and describe.c).


>postgres@postgres(17.0)=# \x \conninfo+
>Expanded display is on.
>Current Connection Information
>-[ RECORD 1 ]------+---------
>Database           | postgres
>Authenticated User | postgres
>System User        |
>Current User       | postgres
>Session User       | postgres
>Session PID        | 951112
>Server Version     | 17devel
>Server Address     |
>Server Port        | 5401
>Client Address     |
>Client Port        |
>Socket Directory   | /tmp
>Host               |

>It looks like "Session PID" is a new term for the server process identifier.
>How about changing the name to "Backend PID" (from pg_backend_pid) or even PID (from pg_stat_activity)?


You're right, it's better to stick with the proper terms already in use
in PostgreSQL. This ensures that the user doesn't get confused. I've
changed it to "Backend PID".


>On 08.02.2024 17:58, Maiquel Grassi wrote:

> 1.
> +                     if (db == NULL)
> +                             printf(_("You are currently not connected to a database.\n"));
>
> This check is performed for \conninfo, but not for \conninfo+.

1. The connection check for the case of \conninfo+ is handled by "describe.c" itself since it deals with queries. I might be mistaken, but I believe that by using "printQuery()" via "describe.c", this is already ensured, and there is no need to evaluate the connection status.

>I found that \conninfo and \conninfo+ act differently when the connection is broken.
>I used pg_terminate_backend function from another session to terminate an open psql session.
>After that, \conninfo does not see the connection break (surprisingly!), and \conninfo+ returns an error:

>postgres@postgres(17.0)=# \conninfo+
>FATAL:  terminating connection due to administrator command
>server closed the connection unexpectedly
        >This probably means the server terminated abnormally
        >before or while processing the request.
>The connection to the server was lost. Attempting reset: Succeeded.


For this case, I believe it's already resolved, because if you get a
return indicating that the connection was terminated, and indeed it was,
then "describe.c" is handling it correctly. At least that's what
it seems like.

>postgres@postgres(17.0)=# \conninfo
>You are connected to database "postgres" as user "postgres" via socket in "/tmp" at port "5401".


Here it seems like we have an issue to be studied and subsequently resolved.

>Another surprise is that this check: if (db == NULL) did not work in both cases.

I will investigate further and, if necessary, remove it.

Here's v12, in the next version, I'll try to address the above situation.

Thanks a lot!
Maiquel Grassi.


Attachments:

  [application/octet-stream] v12-0001-psql-meta-command-conninfo-plus.patch (8.8K, ../CP8P284MB2496D0B0946A4C55D7F0825EEC4B2@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM/3-v12-0001-psql-meta-command-conninfo-plus.patch)
  download | inline diff:
diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index cc7d797..4e86ad9 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1029,10 +1029,14 @@ INSERT INTO tbl1 VALUES ($1, $2) \bind 'first value' 'second value' \g
       </varlistentry>
 
       <varlistentry id="app-psql-meta-command-conninfo">
-        <term><literal>\conninfo</literal></term>
+        <term><literal>\conninfo[+]</literal></term>
         <listitem>
         <para>
         Outputs information about the current database connection.
+        When no <literal>+</literal> is specified, it simply prints
+        a textual description of a few connection options.
+        When <literal>+</literal> is given, more complete information
+        is displayed as a table.
         </para>
         </listitem>
       </varlistentry>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 5c906e4..2c4ea74 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -68,7 +68,8 @@ static backslashResult exec_command_C(PsqlScanState scan_state, bool active_bran
 static backslashResult exec_command_connect(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_cd(PsqlScanState scan_state, bool active_branch,
 									   const char *cmd);
-static backslashResult exec_command_conninfo(PsqlScanState scan_state, bool active_branch);
+static backslashResult exec_command_conninfo(PsqlScanState scan_state, bool active_branch,
+											 const char *cmd);
 static backslashResult exec_command_copy(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_copyright(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_crosstabview(PsqlScanState scan_state, bool active_branch);
@@ -317,8 +318,8 @@ exec_command(const char *cmd,
 		status = exec_command_connect(scan_state, active_branch);
 	else if (strcmp(cmd, "cd") == 0)
 		status = exec_command_cd(scan_state, active_branch, cmd);
-	else if (strcmp(cmd, "conninfo") == 0)
-		status = exec_command_conninfo(scan_state, active_branch);
+	else if (strcmp(cmd, "conninfo") == 0 || strcmp(cmd, "conninfo+") == 0)
+		status = exec_command_conninfo(scan_state, active_branch, cmd);
 	else if (pg_strcasecmp(cmd, "copy") == 0)
 		status = exec_command_copy(scan_state, active_branch);
 	else if (strcmp(cmd, "copyright") == 0)
@@ -643,47 +644,70 @@ exec_command_cd(PsqlScanState scan_state, bool active_branch, const char *cmd)
 }
 
 /*
- * \conninfo -- display information about the current connection
+ * \conninfo, \conninfo+ -- display information about the current connection
  */
 static backslashResult
-exec_command_conninfo(PsqlScanState scan_state, bool active_branch)
+exec_command_conninfo(PsqlScanState scan_state, bool active_branch, const char *cmd)
 {
+	bool		success = true;
+
 	if (active_branch)
 	{
 		char	   *db = PQdb(pset.db);
+		bool		show_verbose;
 
-		if (db == NULL)
-			printf(_("You are currently not connected to a database.\n"));
-		else
+		show_verbose = strchr(cmd, '+') ? true : false;
+
+		/*
+		 * \conninfo+
+		 */
+		if (show_verbose)
 		{
-			char	   *host = PQhost(pset.db);
-			char	   *hostaddr = PQhostaddr(pset.db);
+			success = listConnectionInformation();
+			printSSLInfo();
+			printGSSInfo();
+		}
 
-			if (is_unixsock_path(host))
-			{
-				/* hostaddr overrides host */
-				if (hostaddr && *hostaddr)
-					printf(_("You are connected to database \"%s\" as user \"%s\" on address \"%s\" at port \"%s\".\n"),
-						   db, PQuser(pset.db), hostaddr, PQport(pset.db));
-				else
-					printf(_("You are connected to database \"%s\" as user \"%s\" via socket in \"%s\" at port \"%s\".\n"),
-						   db, PQuser(pset.db), host, PQport(pset.db));
-			}
+		/*
+		 * \conninfo
+		 */
+		else
+		{
+			if (db == NULL)
+				printf(_("You are currently not connected to a database.\n"));
 			else
 			{
-				if (hostaddr && *hostaddr && strcmp(host, hostaddr) != 0)
-					printf(_("You are connected to database \"%s\" as user \"%s\" on host \"%s\" (address \"%s\") at port \"%s\".\n"),
-						   db, PQuser(pset.db), host, hostaddr, PQport(pset.db));
+				char	   *host = PQhost(pset.db);
+				char	   *hostaddr = PQhostaddr(pset.db);
+
+				if (is_unixsock_path(host))
+				{
+					/* hostaddr overrides host */
+					if (hostaddr && *hostaddr)
+						printf(_("You are connected to database \"%s\" as user \"%s\" on address \"%s\" at port \"%s\".\n"),
+							   db, PQuser(pset.db), hostaddr, PQport(pset.db));
+					else
+						printf(_("You are connected to database \"%s\" as user \"%s\" via socket in \"%s\" at port \"%s\".\n"),
+							   db, PQuser(pset.db), host, PQport(pset.db));
+				}
 				else
-					printf(_("You are connected to database \"%s\" as user \"%s\" on host \"%s\" at port \"%s\".\n"),
-						   db, PQuser(pset.db), host, PQport(pset.db));
+				{
+					if (hostaddr && *hostaddr && strcmp(host, hostaddr) != 0)
+						printf(_("You are connected to database \"%s\" as user \"%s\" on host \"%s\" (address \"%s\") at port \"%s\".\n"),
+							   db, PQuser(pset.db), host, hostaddr, PQport(pset.db));
+					else
+						printf(_("You are connected to database \"%s\" as user \"%s\" on host \"%s\" at port \"%s\".\n"),
+							   db, PQuser(pset.db), host, PQport(pset.db));
+				}
+				printSSLInfo();
+				printGSSInfo();
 			}
-			printSSLInfo();
-			printGSSInfo();
 		}
 	}
+	else
+		ignore_slash_options(scan_state);
 
-	return PSQL_CMD_SKIP_LINE;
+	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
 }
 
 /*
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index b6a4eb1..506d9c5 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -26,6 +26,7 @@
 #include "fe_utils/mbprint.h"
 #include "fe_utils/print.h"
 #include "fe_utils/string_utils.h"
+#include "libpq/pqcomm.h"
 #include "settings.h"
 #include "variables.h"
 
@@ -901,6 +902,69 @@ error_return:
 	return false;
 }
 
+/*
+ * listConnectionInformation
+ *
+ * for \conninfo+
+ */
+bool
+listConnectionInformation(void)
+{
+	PGresult   *res;
+	PQExpBufferData buf;
+	printQueryOpt myopt = pset.popt;
+
+	char	   *host = PQhost(pset.db);
+	char	   *hostaddr = PQhostaddr(pset.db);
+
+	initPQExpBuffer(&buf);
+
+	printfPQExpBuffer(&buf,
+					  "SELECT\n"
+					  "  pg_catalog.current_database() AS \"Database\",\n"
+					  "  '%s' AS \"Authenticated User\",\n",
+					  PQuser(pset.db));
+	if (pset.sversion >= 160000)
+		appendPQExpBuffer(&buf,
+						  "  pg_catalog.system_user() AS \"System User\",\n");
+	appendPQExpBuffer(&buf,
+					  "  pg_catalog.current_user() AS \"Current User\",\n"
+					  "  pg_catalog.session_user() AS \"Session User\",\n"
+					  "  pg_catalog.pg_backend_pid() AS \"Backend PID\",\n"
+					  "  pg_catalog.inet_server_addr() AS \"Server Address\",\n"
+					  "  pg_catalog.current_setting('port') AS \"Server Port\",\n"
+					  "  pg_catalog.inet_client_addr() AS \"Client Address\",\n"
+					  "  pg_catalog.inet_client_port() AS \"Client Port\",\n");
+	if (is_unixsock_path(host) && !(hostaddr && *hostaddr))
+		appendPQExpBuffer(&buf,
+						  "  '%s' AS \"Socket Directory\",\n",
+						  host);
+	else
+		appendPQExpBuffer(&buf,
+						  "  NULL AS \"Socket Directory\",\n");
+	appendPQExpBuffer(&buf,
+					  "  CASE\n"
+					  "    WHEN\n"
+					  "      pg_catalog.inet_server_addr() IS NULL\n"
+					  "      AND pg_catalog.inet_client_addr() IS NULL\n"
+					  "    THEN NULL\n"
+					  "    ELSE '%s'\n"
+					  "  END AS \"Host\";",
+					  host);
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.title = _("Current Connection Information");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
 
 /*
  * listAllDbs
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 273f974..8a4e83f 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -64,6 +64,9 @@ extern bool listTSDictionaries(const char *pattern, bool verbose);
 /* \dFt */
 extern bool listTSTemplates(const char *pattern, bool verbose);
 
+/* \conninfo */
+extern bool listConnectionInformation(void);
+
 /* \l */
 extern bool listAllDbs(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 4e79a81..2c5426d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -310,7 +310,7 @@ slashUsage(unsigned short int pager)
 	else
 		HELP0("  \\c[onnect] {[DBNAME|- USER|- HOST|- PORT|-] | conninfo}\n"
 			  "                         connect to new database (currently no connection)\n");
-	HELP0("  \\conninfo              display information about current connection\n");
+	HELP0("  \\conninfo[+]           display information about current connection\n");
 	HELP0("  \\encoding [ENCODING]   show or set client encoding\n");
 	HELP0("  \\password [USERNAME]   securely change the password for a user\n");
 	HELP0("\n");


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  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: RE: Psql meta-command conninfo+
  In-Reply-To: <CP8P284MB2496D0B0946A4C55D7F0825EEC4B2@CP8P284MB2496.BRAP284.PROD.OUTLOOK.COM>

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