From 8ff1dfbaaab139f1796d3b604d7b8c5bdbf0d163 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@otacoo.com>
Date: Mon, 1 Sep 2014 20:53:45 +0900
Subject: [PATCH 2/2] Support for replslot creation and drop in pg_receivexlog

Using the new actions --create and --drop that are similarly present
in pg_recvlogical, a user can respectively create and drop a replication
slot that can be used afterwards when fetching WALs.
---
 doc/src/sgml/ref/pg_receivexlog.sgml   | 29 +++++++++++++++++
 src/bin/pg_basebackup/pg_receivexlog.c | 59 +++++++++++++++++++++++++++++++++-
 2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/pg_receivexlog.sgml b/doc/src/sgml/ref/pg_receivexlog.sgml
index 5916b8f..51d93ea 100644
--- a/doc/src/sgml/ref/pg_receivexlog.sgml
+++ b/doc/src/sgml/ref/pg_receivexlog.sgml
@@ -72,6 +72,35 @@ PostgreSQL documentation
   <title>Options</title>
 
    <para>
+    <application>pg_receivexlog</application> can run in one of two following
+    modes, which control physical replication slot:
+
+    <variablelist>
+
+     <varlistentry>
+      <term><option>--create</option></term>
+      <listitem>
+       <para>
+        Create a new physical replication slot with the name specified in
+        <option>--slot</option>, then exit.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>--drop</option></term>
+      <listitem>
+       <para>
+        Drop the replication slot with the name specified in
+        <option>--slot</option>, then exit.
+       </para>
+      </listitem>
+     </varlistentry>
+    </variablelist>
+
+   </para>
+
+   <para>
     The following command-line options control the location and format of the
     output.
 
diff --git a/src/bin/pg_basebackup/pg_receivexlog.c b/src/bin/pg_basebackup/pg_receivexlog.c
index f722374..e87839a 100644
--- a/src/bin/pg_basebackup/pg_receivexlog.c
+++ b/src/bin/pg_basebackup/pg_receivexlog.c
@@ -38,6 +38,8 @@ static int	noloop = 0;
 static int	standby_message_timeout = 10 * 1000;		/* 10 sec = default */
 static int	fsync_interval = 0; /* 0 = default */
 static volatile bool time_to_abort = false;
+static bool do_create_slot = false;
+static bool do_drop_slot = false;
 
 
 static void usage(void);
@@ -78,6 +80,9 @@ usage(void)
 	printf(_("  -w, --no-password      never prompt for password\n"));
 	printf(_("  -W, --password         force password prompt (should happen automatically)\n"));
 	printf(_("  -S, --slot=SLOTNAME    replication slot to use\n"));
+	printf(_("\nOptional actions:\n"));
+	printf(_("      --create           create a new replication slot (for the slot's name see --slot)\n"));
+	printf(_("      --drop             drop the replication slot (for the slot's name see --slot)\n"));
 	printf(_("\nReport bugs to <pgsql-bugs@postgresql.org>.\n"));
 }
 
@@ -337,6 +342,9 @@ main(int argc, char **argv)
 		{"status-interval", required_argument, NULL, 's'},
 		{"slot", required_argument, NULL, 'S'},
 		{"verbose", no_argument, NULL, 'v'},
+/* action */
+		{"create", no_argument, NULL, 1},
+		{"drop", no_argument, NULL, 2},
 		{NULL, 0, NULL, 0}
 	};
 
@@ -420,6 +428,13 @@ main(int argc, char **argv)
 			case 'v':
 				verbose++;
 				break;
+/* action */
+			case 1:
+				do_create_slot = true;
+				break;
+			case 2:
+				do_drop_slot = true;
+				break;
 			default:
 
 				/*
@@ -444,10 +459,26 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
+	if (replication_slot == NULL && (do_drop_slot || do_create_slot))
+	{
+		fprintf(stderr, _("%s: replication slot needed with action --create or --drop\n"), progname);
+		fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
+				progname);
+		exit(1);
+	}
+
+	if (do_drop_slot && do_create_slot)
+	{
+		fprintf(stderr, _("%s: cannot use --create together with --drop\n"), progname);
+		fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
+				progname);
+		exit(1);
+	}
+
 	/*
 	 * Required arguments
 	 */
-	if (basedir == NULL)
+	if (basedir == NULL && !do_create_slot && !do_drop_slot)
 	{
 		fprintf(stderr, _("%s: no target directory specified\n"), progname);
 		fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
@@ -465,6 +496,32 @@ main(int argc, char **argv)
 		/* Error message already written in GetConnection() */
 		exit(1);
 
+	/* Drop a replication slot */
+	if (do_drop_slot)
+	{
+		if (verbose)
+			fprintf(stderr,
+					_("%s: dropping replication slot \"%s\"\n"),
+					progname, replication_slot);
+
+		if (!DropReplicationSlot(conn, true))
+			disconnect_and_exit(1);
+		disconnect_and_exit(0);
+	}
+
+	/* Create a replication slot */
+	if (do_create_slot)
+	{
+		if (verbose)
+			fprintf(stderr,
+					_("%s: creating replication slot \"%s\"\n"),
+					progname, replication_slot);
+
+		if (!CreateReplicationSlot(conn, NULL, true))
+			disconnect_and_exit(1);
+		disconnect_and_exit(0);
+	}
+
 	while (true)
 	{
 		StreamLog();
-- 
2.1.0