v24-0014-address-comments-from-Vignesh-1.patch

From 6dfad1816c9aaf213b3239490802227beff0d4cc Mon Sep 17 00:00:00 2001
From: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Date: Thu, 22 Feb 2024 10:00:02 +0000
Subject: [PATCH v24 14/18] address comments from Vignesh #1

---
 doc/src/sgml/ref/pg_createsubscriber.sgml   |  7 +++++++
 src/bin/pg_basebackup/pg_createsubscriber.c | 17 ++++++++++++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/pg_createsubscriber.sgml b/doc/src/sgml/ref/pg_createsubscriber.sgml
index 579e50a0a0..4579495089 100644
--- a/doc/src/sgml/ref/pg_createsubscriber.sgml
+++ b/doc/src/sgml/ref/pg_createsubscriber.sgml
@@ -135,6 +135,13 @@ PostgreSQL documentation
     would be removed from a primary instance.
    </para>
 
+   <para>
+    Executing DDL commands while running <application>pg_createsubscriber</application>
+    is not recommended. Because if the physical standby has already been
+    converted to the subscriber, it would not be replicated, so an error
+    would occur.
+   </para>
+
    <para>
     The <application>pg_createsubscriber</application> focuses on large-scale
     systems that contain more data than 1GB.  For smaller systems, initial data
diff --git a/src/bin/pg_basebackup/pg_createsubscriber.c b/src/bin/pg_basebackup/pg_createsubscriber.c
index 4a28dfb81c..a51943106a 100644
--- a/src/bin/pg_basebackup/pg_createsubscriber.c
+++ b/src/bin/pg_basebackup/pg_createsubscriber.c
@@ -1226,9 +1226,13 @@ wait_for_end_recovery(const char *conninfo, const char *pg_ctl_path,
 	if (conn == NULL)
 		exit(1);
 
+#define NUM_ACCEPTABLE_DISCONNECTION 15
+
 	for (;;)
 	{
 		bool			in_recovery;
+		PGresult	   *res;
+		int				count = 0;
 
 		in_recovery = server_is_in_recovery(conn);
 
@@ -1243,6 +1247,16 @@ wait_for_end_recovery(const char *conninfo, const char *pg_ctl_path,
 			break;
 		}
 
+		res = PQexec(conn,
+					 "SELECT count(1) FROM pg_catalog.pg_stat_wal_receiver;");
+
+		if (atoi(PQgetvalue(res, 0, 0)) == 0 &&
+			count++ > NUM_ACCEPTABLE_DISCONNECTION)
+		{
+			stop_standby_server(pg_ctl_path, opt->subscriber_dir);
+			pg_fatal("standby disconnected from the primary");
+		}
+
 		/* Bail out after recovery_timeout seconds if this option is set */
 		if (opt->recovery_timeout > 0 && timer >= opt->recovery_timeout)
 		{
@@ -1251,6 +1265,7 @@ wait_for_end_recovery(const char *conninfo, const char *pg_ctl_path,
 		}
 
 		/* Keep waiting */
+		PQclear(res);
 		pg_usleep(WAIT_INTERVAL * USEC_PER_SEC);
 
 		timer += WAIT_INTERVAL;
@@ -1342,7 +1357,7 @@ drop_publication(PGconn *conn, LogicalRepInfo *dbinfo)
 	pg_log_info("dropping publication \"%s\" on database \"%s\"",
 				dbinfo->pubname, dbinfo->dbname);
 
-	appendPQExpBuffer(str, "DROP PUBLICATION %s", dbinfo->pubname);
+	appendPQExpBuffer(str, "DROP PUBLICATION IF EXISTS %s", dbinfo->pubname);
 
 	pg_log_debug("command is: %s", str->data);
 
-- 
2.43.0