v2-0001-Add-a-new-argument-l-logdir_prefix-to-pg_createsu.patch

From 0dc3ba77d91633958206e1e744d52c01f6a7851f Mon Sep 17 00:00:00 2001
From: Gyan Sreejith <gyan.sreejith@gmail.com>
Date: Mon, 19 Jan 2026 19:49:20 -0500
Subject: [PATCH v2] Add a new argument -l <logdir_prefix> to
 pg_createsubscriber.

Enabling the option to write messages to log files.
A new directory is created by appending the timestamp to the argument, and two new logfiles are added to the directory
1. pg_createsubscriber_server.log  - captures messages related to starting and stopping the standby server.
2. pg_createsubscriber_internal.log - captures internal diagnostic output from pg_createsubscriber.

For example, if we specify -l abc as an argument, and if the timestamp on running it is 2026-01-19-20-43-17.204240,
a directory abc_2026-01-19-20-43-17.20420 is created if it doesn't exist already, and the directory will contain the two log files.
---
 doc/src/sgml/ref/pg_createsubscriber.sgml     |  22 ++
 src/bin/pg_basebackup/pg_createsubscriber.c   | 373 ++++++++++++------
 .../t/040_pg_createsubscriber.pl              |  36 +-
 3 files changed, 319 insertions(+), 112 deletions(-)

diff --git a/doc/src/sgml/ref/pg_createsubscriber.sgml b/doc/src/sgml/ref/pg_createsubscriber.sgml
index e450c6a5b37..4d85da86f09 100644
--- a/doc/src/sgml/ref/pg_createsubscriber.sgml
+++ b/doc/src/sgml/ref/pg_createsubscriber.sgml
@@ -136,6 +136,28 @@ PostgreSQL documentation
      </listitem>
     </varlistentry>
 
+    <varlistentry>
+     <term><option>-l <replaceable class="parameter">directory_prefix</replaceable></option></term>
+     <term><option>--logdir-prefix=<replaceable class="parameter">directory_prefix</replaceable></option></term>
+     <listitem>
+      <para>
+       Specify the prefix to the log directory. A timestamp is added to this prefix and a new directory is created with this name if it does not exist. The following two log files will be created with a umask of 077 so that access is disallowed to other users by default:
+       <itemizedlist>
+        <listitem>
+         <para>
+          pg_createsubscriber_server.log which captures logs related to stopping and starting the standby server,
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          pg_createsubscriber_internal.log which captures internal diagnostic output (validations, checks, etc.)
+         </para>
+        </listitem>
+       </itemizedlist>
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry>
      <term><option>-n</option></term>
      <term><option>--dry-run</option></term>
diff --git a/src/bin/pg_basebackup/pg_createsubscriber.c b/src/bin/pg_basebackup/pg_createsubscriber.c
index 9a825bfd166..9b33cbe537d 100644
--- a/src/bin/pg_basebackup/pg_createsubscriber.c
+++ b/src/bin/pg_basebackup/pg_createsubscriber.c
@@ -33,10 +33,35 @@
 #define	DEFAULT_SUB_PORT	"50432"
 #define	OBJECTTYPE_PUBLICATIONS  0x0001
 
+#define SERVER_LOG_FILE_NAME "pg_createsubscriber_server.log"
+#define INTERNAL_LOG_FILE_NAME "pg_createsubscriber_internal.log"
+
+#define INFO(...) do{\
+	if (internal_log_file_fp != NULL) \
+		internal_log_file_write(__VA_ARGS__); \
+	else \
+		pg_log_info(__VA_ARGS__);\
+} while(0)
+
+#define INFO_HINT(...) do{\
+	if (internal_log_file_fp != NULL) \
+		internal_log_file_write(__VA_ARGS__); \
+	else \
+		pg_log_info_hint(__VA_ARGS__);\
+} while(0)
+
+#define DEBUG(...) do{\
+	if (internal_log_file_fp != NULL) \
+		internal_log_file_write(__VA_ARGS__); \
+	else \
+		pg_log_debug(__VA_ARGS__);\
+} while(0)
+
 /* Command-line options */
 struct CreateSubscriberOptions
 {
 	char	   *config_file;	/* configuration file */
+	char	   *log_dir;		/* log directory name */
 	char	   *pub_conninfo_str;	/* publisher connection string */
 	char	   *socket_dir;		/* directory for Unix-domain socket, if any */
 	char	   *sub_port;		/* subscriber port number */
@@ -130,6 +155,9 @@ static void drop_existing_subscription(PGconn *conn, const char *subname,
 									   const char *dbname);
 static void get_publisher_databases(struct CreateSubscriberOptions *opt,
 									bool dbnamespecified);
+static void
+			internal_log_file_write(const char *format,...) __attribute__((format(printf, 1, 2)));
+
 
 #define	WAIT_INTERVAL	1		/* 1 second */
 
@@ -151,12 +179,86 @@ static pg_prng_state prng_state;
 static char *pg_ctl_path = NULL;
 static char *pg_resetwal_path = NULL;
 
+static FILE *internal_log_file_fp = NULL;	/* File ptr to log all messages to */
+
 /* standby / subscriber data directory */
 static char *subscriber_dir = NULL;
 
 static bool recovery_ended = false;
 static bool standby_running = false;
 
+/*
+ * Print the current time, with microseconds, into a caller-supplied
+ * buffer.
+ * Same as pq_TraceFormatTimestamp() in src/interfaces/libfq/fe-trace.c
+ */
+static void
+populate_timestamp(char *timestr, size_t ts_len)
+{
+	struct timeval tval;
+	time_t		now;
+	struct tm	tmbuf;
+
+	gettimeofday(&tval, NULL);
+
+	/*
+	 * MSVC's implementation of timeval uses a long for tv_sec, however,
+	 * localtime() expects a time_t pointer.  Here we'll assign tv_sec to a
+	 * local time_t variable so that we pass localtime() the correct pointer
+	 * type.
+	 */
+	now = tval.tv_sec;
+	strftime(timestr, ts_len,
+			 "%Y-%m-%d-%H-%M-%S",
+			 localtime_r(&now, &tmbuf));
+	/* append microseconds */
+	snprintf(timestr + strlen(timestr), ts_len - strlen(timestr),
+			 ".%06u", (unsigned int) (tval.tv_usec));
+}
+
+static void
+internal_log_file_write(const char *format,...)
+{
+	if (internal_log_file_fp != NULL)
+	{
+		va_list		args;
+
+		va_start(args, format);
+		vfprintf(internal_log_file_fp, format, args);
+		fprintf(internal_log_file_fp, "\n");
+		va_end(args);
+	}
+}
+
+/*
+ * Open a new logfile with proper permissions.
+ * From src/backend/postmaster/syslogger.c
+ */
+static FILE *
+logfile_open(const char *filename, const char *mode)
+{
+	FILE	   *fh;
+	mode_t		oumask;
+
+	oumask = umask((mode_t) ((~(S_IRUSR | S_IWUSR)) & (S_IRWXU | S_IRWXG | S_IRWXO)));
+	fh = fopen(filename, mode);
+	umask(oumask);
+
+	if (fh)
+	{
+		setvbuf(fh, NULL, PG_IOLBF, 0);
+
+#ifdef WIN32
+		/* use CRLF line endings on Windows */
+		_setmode(_fileno(fh), _O_TEXT);
+#endif
+	}
+	else
+		pg_fatal("could not open log file \"%s\": %m",
+				 filename);
+
+	return fh;
+}
 
 /*
  * Cleanup objects that were created by pg_createsubscriber if there is an
@@ -175,6 +277,9 @@ cleanup_objects_atexit(void)
 	if (success)
 		return;
 
+	if (internal_log_file_fp != NULL)
+		fclose(internal_log_file_fp);
+
 	/*
 	 * If the server is promoted, there is no way to use the current setup
 	 * again. Warn the user that a new replication setup should be done before
@@ -246,6 +351,8 @@ usage(void)
 			 "                                  databases and databases that don't allow connections\n"));
 	printf(_("  -d, --database=DBNAME           database in which to create a subscription\n"));
 	printf(_("  -D, --pgdata=DATADIR            location for the subscriber data directory\n"));
+	printf(_("  -l, --logdir-prefix=LOGDIRPREFIX prefix for the new log directory. The timestamp will be \n"
+			 "appended to this prefix to get the name of the log directory\n"));
 	printf(_("  -n, --dry-run                   dry run, just show what would be done\n"));
 	printf(_("  -p, --subscriber-port=PORT      subscriber port number (default %s)\n"), DEFAULT_SUB_PORT);
 	printf(_("  -P, --publisher-server=CONNSTR  publisher connection string\n"));
@@ -389,7 +496,7 @@ get_exec_path(const char *argv0, const char *progname)
 					 progname, full_path, "pg_createsubscriber");
 	}
 
-	pg_log_debug("%s path is:  %s", progname, exec_path);
+	DEBUG("%s path is:  %s", progname, exec_path);
 
 	return exec_path;
 }
@@ -406,8 +513,8 @@ check_data_directory(const char *datadir)
 	uint32		major_version;
 	char	   *version_str;
 
-	pg_log_info("checking if directory \"%s\" is a cluster data directory",
-				datadir);
+	INFO("checking if directory \"%s\" is a cluster data directory",
+		 datadir);
 
 	if (stat(datadir, &statbuf) != 0)
 	{
@@ -510,14 +617,14 @@ store_pub_sub_info(const struct CreateSubscriberOptions *opt,
 			dbinfo[i].subname = NULL;
 		/* Other fields will be filled later */
 
-		pg_log_debug("publisher(%d): publication: %s ; replication slot: %s ; connection string: %s", i,
-					 dbinfo[i].pubname ? dbinfo[i].pubname : "(auto)",
-					 dbinfo[i].replslotname ? dbinfo[i].replslotname : "(auto)",
-					 dbinfo[i].pubconninfo);
-		pg_log_debug("subscriber(%d): subscription: %s ; connection string: %s, two_phase: %s", i,
-					 dbinfo[i].subname ? dbinfo[i].subname : "(auto)",
-					 dbinfo[i].subconninfo,
-					 dbinfos.two_phase ? "true" : "false");
+		DEBUG("publisher(%d): publication: %s ; replication slot: %s ; connection string: %s", i,
+			  dbinfo[i].pubname ? dbinfo[i].pubname : "(auto)",
+			  dbinfo[i].replslotname ? dbinfo[i].replslotname : "(auto)",
+			  dbinfo[i].pubconninfo);
+		DEBUG("subscriber(%d): subscription: %s ; connection string: %s, two_phase: %s", i,
+			  dbinfo[i].subname ? dbinfo[i].subname : "(auto)",
+			  dbinfo[i].subconninfo,
+			  dbinfos.two_phase ? "true" : "false");
 
 		if (num_pubs > 0)
 			pubcell = pubcell->next;
@@ -598,7 +705,7 @@ get_primary_sysid(const char *conninfo)
 	PGresult   *res;
 	uint64		sysid;
 
-	pg_log_info("getting system identifier from publisher");
+	INFO("getting system identifier from publisher");
 
 	conn = connect_database(conninfo, true);
 
@@ -618,7 +725,7 @@ get_primary_sysid(const char *conninfo)
 
 	sysid = strtou64(PQgetvalue(res, 0, 0), NULL, 10);
 
-	pg_log_info("system identifier is %" PRIu64 " on publisher", sysid);
+	INFO("system identifier is %" PRIu64 " on publisher", sysid);
 
 	PQclear(res);
 	disconnect_database(conn, false);
@@ -638,7 +745,7 @@ get_standby_sysid(const char *datadir)
 	bool		crc_ok;
 	uint64		sysid;
 
-	pg_log_info("getting system identifier from subscriber");
+	INFO("getting system identifier from subscriber");
 
 	cf = get_controlfile(datadir, &crc_ok);
 	if (!crc_ok)
@@ -646,7 +753,7 @@ get_standby_sysid(const char *datadir)
 
 	sysid = cf->system_identifier;
 
-	pg_log_info("system identifier is %" PRIu64 " on subscriber", sysid);
+	INFO("system identifier is %" PRIu64 " on subscriber", sysid);
 
 	pg_free(cf);
 
@@ -665,9 +772,10 @@ modify_subscriber_sysid(const struct CreateSubscriberOptions *opt)
 	bool		crc_ok;
 	struct timeval tv;
 
+	char	   *out_file;
 	char	   *cmd_str;
 
-	pg_log_info("modifying system identifier of subscriber");
+	INFO("modifying system identifier of subscriber");
 
 	cf = get_controlfile(subscriber_dir, &crc_ok);
 	if (!crc_ok)
@@ -676,7 +784,7 @@ modify_subscriber_sysid(const struct CreateSubscriberOptions *opt)
 	/*
 	 * Select a new system identifier.
 	 *
-	 * XXX this code was extracted from BootStrapXLOG().
+	 * XXX this code was extracted from BootStrapXINFO().
 	 */
 	gettimeofday(&tv, NULL);
 	cf->system_identifier = ((uint64) tv.tv_sec) << 32;
@@ -684,31 +792,37 @@ modify_subscriber_sysid(const struct CreateSubscriberOptions *opt)
 	cf->system_identifier |= getpid() & 0xFFF;
 
 	if (dry_run)
-		pg_log_info("dry-run: would set system identifier to %" PRIu64 " on subscriber",
-					cf->system_identifier);
+		INFO("dry-run: would set system identifier to %" PRIu64 " on subscriber",
+			 cf->system_identifier);
 	else
 	{
 		update_controlfile(subscriber_dir, cf, true);
-		pg_log_info("system identifier is %" PRIu64 " on subscriber",
-					cf->system_identifier);
+		INFO("system identifier is %" PRIu64 " on subscriber",
+			 cf->system_identifier);
 	}
 
 	if (dry_run)
-		pg_log_info("dry-run: would run pg_resetwal on the subscriber");
+		INFO("dry-run: would run pg_resetwal on the subscriber");
 	else
-		pg_log_info("running pg_resetwal on the subscriber");
+		INFO("running pg_resetwal on the subscriber");
+
 
-	cmd_str = psprintf("\"%s\" -D \"%s\" > \"%s\"", pg_resetwal_path,
-					   subscriber_dir, DEVNULL);
+	if (opt->log_dir != NULL)
+		out_file = psprintf("%s/%s", opt->log_dir, SERVER_LOG_FILE_NAME);
+	else
+		out_file = DEVNULL;
 
-	pg_log_debug("pg_resetwal command is: %s", cmd_str);
+	cmd_str = psprintf("\"%s\" -D \"%s\" >> \"%s\"", pg_resetwal_path,
+					   subscriber_dir, out_file);
+
+	DEBUG("pg_resetwal command is: %s", cmd_str);
 
 	if (!dry_run)
 	{
 		int			rc = system(cmd_str);
 
 		if (rc == 0)
-			pg_log_info("successfully reset WAL on the subscriber");
+			INFO("successfully reset WAL on the subscriber");
 		else
 			pg_fatal("could not reset WAL on subscriber: %s", wait_result_to_str(rc));
 	}
@@ -836,8 +950,8 @@ setup_publisher(struct LogicalRepInfo *dbinfo)
 		if (find_publication(conn, dbinfo[i].pubname, dbinfo[i].dbname))
 		{
 			/* Reuse existing publication on publisher. */
-			pg_log_info("use existing publication \"%s\" in database \"%s\"",
-						dbinfo[i].pubname, dbinfo[i].dbname);
+			INFO("use existing publication \"%s\" in database \"%s\"",
+				 dbinfo[i].pubname, dbinfo[i].dbname);
 			/* Don't remove pre-existing publication if an error occurs. */
 			dbinfo[i].made_publication = false;
 		}
@@ -934,7 +1048,7 @@ check_publisher(const struct LogicalRepInfo *dbinfo)
 	int			max_prepared_transactions;
 	char	   *max_slot_wal_keep_size;
 
-	pg_log_info("checking settings on publisher");
+	INFO("checking settings on publisher");
 
 	conn = connect_database(dbinfo[0].pubconninfo, true);
 
@@ -985,15 +1099,15 @@ check_publisher(const struct LogicalRepInfo *dbinfo)
 
 	PQclear(res);
 
-	pg_log_debug("publisher: wal_level: %s", wal_level);
-	pg_log_debug("publisher: max_replication_slots: %d", max_repslots);
-	pg_log_debug("publisher: current replication slots: %d", cur_repslots);
-	pg_log_debug("publisher: max_wal_senders: %d", max_walsenders);
-	pg_log_debug("publisher: current wal senders: %d", cur_walsenders);
-	pg_log_debug("publisher: max_prepared_transactions: %d",
-				 max_prepared_transactions);
-	pg_log_debug("publisher: max_slot_wal_keep_size: %s",
-				 max_slot_wal_keep_size);
+	DEBUG("publisher: wal_level: %s", wal_level);
+	DEBUG("publisher: max_replication_slots: %d", max_repslots);
+	DEBUG("publisher: current replication slots: %d", cur_repslots);
+	DEBUG("publisher: max_wal_senders: %d", max_walsenders);
+	DEBUG("publisher: current wal senders: %d", cur_walsenders);
+	DEBUG("publisher: max_prepared_transactions: %d",
+		  max_prepared_transactions);
+	DEBUG("publisher: max_slot_wal_keep_size: %s",
+		  max_slot_wal_keep_size);
 
 	disconnect_database(conn, false);
 
@@ -1069,7 +1183,7 @@ check_subscriber(const struct LogicalRepInfo *dbinfo)
 	int			max_reporigins;
 	int			max_wprocs;
 
-	pg_log_info("checking settings on subscriber");
+	INFO("checking settings on subscriber\n");
 
 	conn = connect_database(dbinfo[0].subconninfo, true);
 
@@ -1111,12 +1225,12 @@ check_subscriber(const struct LogicalRepInfo *dbinfo)
 	if (strcmp(PQgetvalue(res, 3, 0), "") != 0)
 		primary_slot_name = pg_strdup(PQgetvalue(res, 3, 0));
 
-	pg_log_debug("subscriber: max_logical_replication_workers: %d",
-				 max_lrworkers);
-	pg_log_debug("subscriber: max_active_replication_origins: %d", max_reporigins);
-	pg_log_debug("subscriber: max_worker_processes: %d", max_wprocs);
+	DEBUG("subscriber: max_logical_replication_workers: %d",
+		  max_lrworkers);
+	DEBUG("subscriber: max_active_replication_origins: %d", max_reporigins);
+	DEBUG("subscriber: max_worker_processes: %d", max_wprocs);
 	if (primary_slot_name)
-		pg_log_debug("subscriber: primary_slot_name: %s", primary_slot_name);
+		DEBUG("subscriber: primary_slot_name: %s", primary_slot_name);
 
 	PQclear(res);
 
@@ -1178,12 +1292,12 @@ drop_existing_subscription(PGconn *conn, const char *subname, const char *dbname
 	appendPQExpBuffer(query, " DROP SUBSCRIPTION %s;", subname);
 
 	if (dry_run)
-		pg_log_info("dry-run: would drop subscription \"%s\" in database \"%s\"",
-					subname, dbname);
+		INFO("dry-run: would drop subscription \"%s\" in database \"%s\"",
+			 subname, dbname);
 	else
 	{
-		pg_log_info("dropping subscription \"%s\" in database \"%s\"",
-					subname, dbname);
+		INFO("dropping subscription \"%s\" in database \"%s\"",
+			 subname, dbname);
 
 		res = PQexec(conn, query->data);
 
@@ -1338,7 +1452,7 @@ setup_recovery(const struct LogicalRepInfo *dbinfo, const char *datadir, const c
 	}
 	disconnect_database(conn, false);
 
-	pg_log_debug("recovery parameters:\n%s", recoveryconfcontents->data);
+	DEBUG("recovery parameters:\n%s", recoveryconfcontents->data);
 }
 
 /*
@@ -1432,11 +1546,11 @@ create_logical_replication_slot(PGconn *conn, struct LogicalRepInfo *dbinfo)
 	Assert(conn != NULL);
 
 	if (dry_run)
-		pg_log_info("dry-run: would create the replication slot \"%s\" in database \"%s\" on publisher",
-					slot_name, dbinfo->dbname);
+		INFO("dry-run: would create the replication slot \"%s\" in database \"%s\" on publisher",
+			 slot_name, dbinfo->dbname);
 	else
-		pg_log_info("creating the replication slot \"%s\" in database \"%s\" on publisher",
-					slot_name, dbinfo->dbname);
+		INFO("creating the replication slot \"%s\" in database \"%s\" on publisher",
+			 slot_name, dbinfo->dbname);
 
 	slot_name_esc = PQescapeLiteral(conn, slot_name, strlen(slot_name));
 
@@ -1447,7 +1561,7 @@ create_logical_replication_slot(PGconn *conn, struct LogicalRepInfo *dbinfo)
 
 	PQfreemem(slot_name_esc);
 
-	pg_log_debug("command is: %s", str->data);
+	DEBUG("command is: %s", str->data);
 
 	if (!dry_run)
 	{
@@ -1485,11 +1599,11 @@ drop_replication_slot(PGconn *conn, struct LogicalRepInfo *dbinfo,
 	Assert(conn != NULL);
 
 	if (dry_run)
-		pg_log_info("dry-run: would drop the replication slot \"%s\" in database \"%s\"",
-					slot_name, dbinfo->dbname);
+		INFO("dry-run: would drop the replication slot \"%s\" in database \"%s\"",
+			 slot_name, dbinfo->dbname);
 	else
-		pg_log_info("dropping the replication slot \"%s\" in database \"%s\"",
-					slot_name, dbinfo->dbname);
+		INFO("dropping the replication slot \"%s\" in database \"%s\"",
+			 slot_name, dbinfo->dbname);
 
 	slot_name_esc = PQescapeLiteral(conn, slot_name, strlen(slot_name));
 
@@ -1497,7 +1611,7 @@ drop_replication_slot(PGconn *conn, struct LogicalRepInfo *dbinfo,
 
 	PQfreemem(slot_name_esc);
 
-	pg_log_debug("command is: %s", str->data);
+	DEBUG("command is: %s", str->data);
 
 	if (!dry_run)
 	{
@@ -1588,12 +1702,17 @@ start_standby_server(const struct CreateSubscriberOptions *opt, bool restricted_
 	if (restrict_logical_worker)
 		appendPQExpBufferStr(pg_ctl_cmd, " -o \"-c max_logical_replication_workers=0\"");
 
-	pg_log_debug("pg_ctl command is: %s", pg_ctl_cmd->data);
+	if (opt->log_dir != NULL)
+	{
+		appendPQExpBuffer(pg_ctl_cmd, " -l %s/%s", opt->log_dir, SERVER_LOG_FILE_NAME);
+	}
+
+	DEBUG("pg_ctl command is: %s", pg_ctl_cmd->data);
 	rc = system(pg_ctl_cmd->data);
 	pg_ctl_status(pg_ctl_cmd->data, rc);
 	standby_running = true;
 	destroyPQExpBuffer(pg_ctl_cmd);
-	pg_log_info("server was started");
+	INFO("server was started");
 }
 
 static void
@@ -1604,11 +1723,11 @@ stop_standby_server(const char *datadir)
 
 	pg_ctl_cmd = psprintf("\"%s\" stop -D \"%s\" -s", pg_ctl_path,
 						  datadir);
-	pg_log_debug("pg_ctl command is: %s", pg_ctl_cmd);
+	DEBUG("pg_ctl command is: %s", pg_ctl_cmd);
 	rc = system(pg_ctl_cmd);
 	pg_ctl_status(pg_ctl_cmd, rc);
 	standby_running = false;
-	pg_log_info("server was stopped");
+	INFO("server was stopped");
 }
 
 /*
@@ -1627,7 +1746,7 @@ wait_for_end_recovery(const char *conninfo, const struct CreateSubscriberOptions
 	bool		ready = false;
 	int			timer = 0;
 
-	pg_log_info("waiting for the target server to reach the consistent state");
+	INFO("waiting for the target server to reach the consistent state");
 
 	conn = connect_database(conninfo, true);
 
@@ -1659,8 +1778,8 @@ wait_for_end_recovery(const char *conninfo, const struct CreateSubscriberOptions
 	if (!ready)
 		pg_fatal("server did not end recovery");
 
-	pg_log_info("target server reached the consistent state");
-	pg_log_info_hint("If pg_createsubscriber fails after this point, you must recreate the physical replica before continuing.");
+	INFO("target server reached the consistent state");
+	INFO_HINT("If pg_createsubscriber fails after this point, you must recreate the physical replica before continuing.");
 }
 
 /*
@@ -1710,16 +1829,16 @@ create_publication(PGconn *conn, struct LogicalRepInfo *dbinfo)
 	resetPQExpBuffer(str);
 
 	if (dry_run)
-		pg_log_info("dry-run: would create publication \"%s\" in database \"%s\"",
-					dbinfo->pubname, dbinfo->dbname);
+		INFO("dry-run: would create publication \"%s\" in database \"%s\"",
+			 dbinfo->pubname, dbinfo->dbname);
 	else
-		pg_log_info("creating publication \"%s\" in database \"%s\"",
-					dbinfo->pubname, dbinfo->dbname);
+		INFO("creating publication \"%s\" in database \"%s\"",
+			 dbinfo->pubname, dbinfo->dbname);
 
 	appendPQExpBuffer(str, "CREATE PUBLICATION %s FOR ALL TABLES",
 					  ipubname_esc);
 
-	pg_log_debug("command is: %s", str->data);
+	DEBUG("command is: %s", str->data);
 
 	if (!dry_run)
 	{
@@ -1757,17 +1876,17 @@ drop_publication(PGconn *conn, const char *pubname, const char *dbname,
 	pubname_esc = PQescapeIdentifier(conn, pubname, strlen(pubname));
 
 	if (dry_run)
-		pg_log_info("dry-run: would drop publication \"%s\" in database \"%s\"",
-					pubname, dbname);
+		INFO("dry-run: would drop publication \"%s\" in database \"%s\"",
+			 pubname, dbname);
 	else
-		pg_log_info("dropping publication \"%s\" in database \"%s\"",
-					pubname, dbname);
+		INFO("dropping publication \"%s\" in database \"%s\"",
+			 pubname, dbname);
 
 	appendPQExpBuffer(str, "DROP PUBLICATION %s", pubname_esc);
 
 	PQfreemem(pubname_esc);
 
-	pg_log_debug("command is: %s", str->data);
+	DEBUG("command is: %s", str->data);
 
 	if (!dry_run)
 	{
@@ -1810,8 +1929,8 @@ check_and_drop_publications(PGconn *conn, struct LogicalRepInfo *dbinfo)
 
 	if (drop_all_pubs)
 	{
-		pg_log_info("dropping all existing publications in database \"%s\"",
-					dbinfo->dbname);
+		INFO("dropping all existing publications in database \"%s\"",
+			 dbinfo->dbname);
 
 		/* Fetch all publication names */
 		res = PQexec(conn, "SELECT pubname FROM pg_catalog.pg_publication;");
@@ -1841,11 +1960,11 @@ check_and_drop_publications(PGconn *conn, struct LogicalRepInfo *dbinfo)
 		else
 		{
 			if (dry_run)
-				pg_log_info("dry-run: would preserve existing publication \"%s\" in database \"%s\"",
-							dbinfo->pubname, dbinfo->dbname);
+				INFO("dry-run: would preserve existing publication \"%s\" in database \"%s\"",
+					 dbinfo->pubname, dbinfo->dbname);
 			else
-				pg_log_info("preserve existing publication \"%s\" in database \"%s\"",
-							dbinfo->pubname, dbinfo->dbname);
+				INFO("preserve existing publication \"%s\" in database \"%s\"",
+					 dbinfo->pubname, dbinfo->dbname);
 		}
 	}
 }
@@ -1879,11 +1998,11 @@ create_subscription(PGconn *conn, const struct LogicalRepInfo *dbinfo)
 	replslotname_esc = PQescapeLiteral(conn, dbinfo->replslotname, strlen(dbinfo->replslotname));
 
 	if (dry_run)
-		pg_log_info("dry-run: would create subscription \"%s\" in database \"%s\"",
-					dbinfo->subname, dbinfo->dbname);
+		INFO("dry-run: would create subscription \"%s\" in database \"%s\"",
+			 dbinfo->subname, dbinfo->dbname);
 	else
-		pg_log_info("creating subscription \"%s\" in database \"%s\"",
-					dbinfo->subname, dbinfo->dbname);
+		INFO("creating subscription \"%s\" in database \"%s\"",
+			 dbinfo->subname, dbinfo->dbname);
 
 	appendPQExpBuffer(str,
 					  "CREATE SUBSCRIPTION %s CONNECTION %s PUBLICATION %s "
@@ -1897,7 +2016,7 @@ create_subscription(PGconn *conn, const struct LogicalRepInfo *dbinfo)
 	PQfreemem(pubconninfo_esc);
 	PQfreemem(replslotname_esc);
 
-	pg_log_debug("command is: %s", str->data);
+	DEBUG("command is: %s", str->data);
 
 	if (!dry_run)
 	{
@@ -1981,18 +2100,18 @@ set_replication_progress(PGconn *conn, const struct LogicalRepInfo *dbinfo, cons
 	originname = psprintf("pg_%u", suboid);
 
 	if (dry_run)
-		pg_log_info("dry-run: would set the replication progress (node name \"%s\", LSN %s) in database \"%s\"",
-					originname, lsnstr, dbinfo->dbname);
+		INFO("dry-run: would set the replication progress (node name \"%s\", LSN %s) in database \"%s\"",
+			 originname, lsnstr, dbinfo->dbname);
 	else
-		pg_log_info("setting the replication progress (node name \"%s\", LSN %s) in database \"%s\"",
-					originname, lsnstr, dbinfo->dbname);
+		INFO("setting the replication progress (node name \"%s\", LSN %s) in database \"%s\"",
+			 originname, lsnstr, dbinfo->dbname);
 
 	resetPQExpBuffer(str);
 	appendPQExpBuffer(str,
 					  "SELECT pg_catalog.pg_replication_origin_advance('%s', '%s')",
 					  originname, lsnstr);
 
-	pg_log_debug("command is: %s", str->data);
+	DEBUG("command is: %s", str->data);
 
 	if (!dry_run)
 	{
@@ -2031,15 +2150,15 @@ enable_subscription(PGconn *conn, const struct LogicalRepInfo *dbinfo)
 	subname = PQescapeIdentifier(conn, dbinfo->subname, strlen(dbinfo->subname));
 
 	if (dry_run)
-		pg_log_info("dry-run: would enable subscription \"%s\" in database \"%s\"",
-					dbinfo->subname, dbinfo->dbname);
+		INFO("dry-run: would enable subscription \"%s\" in database \"%s\"",
+			 dbinfo->subname, dbinfo->dbname);
 	else
-		pg_log_info("enabling subscription \"%s\" in database \"%s\"",
-					dbinfo->subname, dbinfo->dbname);
+		INFO("enabling subscription \"%s\" in database \"%s\"",
+			 dbinfo->subname, dbinfo->dbname);
 
 	appendPQExpBuffer(str, "ALTER SUBSCRIPTION %s ENABLE", subname);
 
-	pg_log_debug("command is: %s", str->data);
+	DEBUG("command is: %s", str->data);
 
 	if (!dry_run)
 	{
@@ -2119,6 +2238,7 @@ main(int argc, char **argv)
 		{"all", no_argument, NULL, 'a'},
 		{"database", required_argument, NULL, 'd'},
 		{"pgdata", required_argument, NULL, 'D'},
+		{"logdir-prefix", required_argument, NULL, 'l'},
 		{"dry-run", no_argument, NULL, 'n'},
 		{"subscriber-port", required_argument, NULL, 'p'},
 		{"publisher-server", required_argument, NULL, 'P'},
@@ -2153,6 +2273,7 @@ main(int argc, char **argv)
 	char	   *consistent_lsn;
 
 	char		pidfile[MAXPGPATH];
+	char	   *internal_log_file;
 
 	pg_logging_init(argv[0]);
 	pg_logging_set_level(PG_LOG_WARNING);
@@ -2177,6 +2298,7 @@ main(int argc, char **argv)
 	/* Default settings */
 	subscriber_dir = NULL;
 	opt.config_file = NULL;
+	opt.log_dir = NULL;
 	opt.pub_conninfo_str = NULL;
 	opt.socket_dir = NULL;
 	opt.sub_port = DEFAULT_SUB_PORT;
@@ -2205,9 +2327,12 @@ main(int argc, char **argv)
 
 	get_restricted_token();
 
-	while ((c = getopt_long(argc, argv, "ad:D:np:P:s:t:TU:v",
+	while ((c = getopt_long(argc, argv, "ad:D:l:np:P:s:t:TU:v",
 							long_options, &option_index)) != -1)
 	{
+		char		timestamp[128];
+		char	   *log_dir;
+
 		switch (c)
 		{
 			case 'a':
@@ -2225,6 +2350,29 @@ main(int argc, char **argv)
 			case 'D':
 				subscriber_dir = pg_strdup(optarg);
 				canonicalize_path(subscriber_dir);
+				break;
+			case 'l':
+				populate_timestamp(timestamp, sizeof(timestamp));
+				log_dir = psprintf("%s_%s", optarg, timestamp);
+				opt.log_dir = pg_strdup(log_dir);
+				canonicalize_path(opt.log_dir);
+
+				if (stat(opt.log_dir, &statbuf) != 0)
+				{
+					if (errno == ENOENT)
+					{
+						mkdir(opt.log_dir, S_IRWXU);
+						INFO("log directory created");
+					}
+					else if (errno == EACCES)
+						pg_fatal("permission denied trying to access directory \"%s\": %m", opt.log_dir);
+					else
+						pg_fatal("could not access directory \"%s\": %m", opt.log_dir);
+				}
+				internal_log_file = psprintf("%s/%s", opt.log_dir, INTERNAL_LOG_FILE_NAME);
+				if ((internal_log_file_fp = logfile_open(internal_log_file, "a")) == NULL)
+					pg_fatal("could not open log file \"%s\": %m", internal_log_file);
+
 				break;
 			case 'n':
 				dry_run = true;
@@ -2363,16 +2511,16 @@ main(int argc, char **argv)
 	}
 
 	if (dry_run)
-		pg_log_info("Executing in dry-run mode.\n"
-					"The target directory will not be modified.");
+		INFO("Executing in dry-run mode.\n"
+			 "The target directory will not be modified.");
 
-	pg_log_info("validating publisher connection string");
+	INFO("validating publisher connection string");
 	pub_base_conninfo = get_base_conninfo(opt.pub_conninfo_str,
 										  &dbname_conninfo);
 	if (pub_base_conninfo == NULL)
 		exit(1);
 
-	pg_log_info("validating subscriber connection string");
+	INFO("validating subscriber connection string");
 	sub_base_conninfo = get_sub_conninfo(&opt);
 
 	/*
@@ -2389,7 +2537,7 @@ main(int argc, char **argv)
 
 	if (opt.database_names.head == NULL)
 	{
-		pg_log_info("no database was specified");
+		INFO("no database was specified");
 
 		/*
 		 * Try to obtain the dbname from the publisher conninfo. If dbname
@@ -2400,8 +2548,8 @@ main(int argc, char **argv)
 			simple_string_list_append(&opt.database_names, dbname_conninfo);
 			num_dbs++;
 
-			pg_log_info("database name \"%s\" was extracted from the publisher connection string",
-						dbname_conninfo);
+			INFO("database name \"%s\" was extracted from the publisher connection string",
+				 dbname_conninfo);
 		}
 		else
 		{
@@ -2498,7 +2646,7 @@ main(int argc, char **argv)
 	 * by command-line options). The goal is to avoid connections during the
 	 * transformation steps.
 	 */
-	pg_log_info("starting the standby server with command-line options");
+	INFO("starting the standby server with command-line options");
 	start_standby_server(&opt, true, false);
 
 	/* Check if the standby server is ready for logical replication */
@@ -2514,7 +2662,7 @@ main(int argc, char **argv)
 	 * guarantees it) *before* creating the replication slots in
 	 * setup_publisher().
 	 */
-	pg_log_info("stopping the subscriber");
+	INFO("stopping the subscriber");
 	stop_standby_server(subscriber_dir);
 
 	/* Create the required objects for each database on publisher */
@@ -2528,7 +2676,7 @@ main(int argc, char **argv)
 	 * until accepting connections. We don't want to start logical replication
 	 * during setup.
 	 */
-	pg_log_info("starting the subscriber");
+	INFO("starting the subscriber");
 	start_standby_server(&opt, true, true);
 
 	/* Waiting the subscriber to be promoted */
@@ -2549,7 +2697,7 @@ main(int argc, char **argv)
 	drop_failover_replication_slots(dbinfos.dbinfo);
 
 	/* Stop the subscriber */
-	pg_log_info("stopping the subscriber");
+	INFO("stopping the subscriber");
 	stop_standby_server(subscriber_dir);
 
 	/* Change system identifier from subscriber */
@@ -2557,7 +2705,10 @@ main(int argc, char **argv)
 
 	success = true;
 
-	pg_log_info("Done!");
+	INFO("Done!");
+
+	if (internal_log_file_fp != NULL)
+		fclose(internal_log_file_fp);
 
 	return 0;
 }
diff --git a/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl b/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
index a905183b738..ed4f382f1af 100644
--- a/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
+++ b/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
@@ -13,7 +13,8 @@ program_help_ok('pg_createsubscriber');
 program_version_ok('pg_createsubscriber');
 program_options_handling_ok('pg_createsubscriber');
 
-my $datadir = PostgreSQL::Test::Utils::tempdir;
+my $datadir = PostgreSQL::Test::Utils::tempdir + "/datadir";
+my $logdir = PostgreSQL::Test::Utils::tempdir + "/logdir";
 
 # Generate a database with a name made of a range of ASCII characters.
 # Extracted from 002_pg_upgrade.pl.
@@ -579,10 +580,43 @@ is($result, qq($db1|{test_pub3}
 $db2|{pub2}),
 	"subscriptions use the correct publications");
 
+$node_p->backup('backup_3');
+
+# Set up node R as a logical replica node
+my $node_r = PostgreSQL::Test::Cluster->new('node_r');
+$node_r->init_from_backup($node_p, 'backup_3', has_streaming => 1);
+$node_r->append_conf(
+	'postgresql.conf', qq[
+primary_conninfo = '$pconnstr dbname=postgres'
+hot_standby_feedback = on
+]);
+$node_r->set_standby_mode();
+
+# Test that --logdir works for pg_createsubscriber
+command_ok(
+	[
+		'pg_createsubscriber',
+		'--verbose',
+		'--pgdata' => $node_r->data_dir,
+		'--publisher-server' => $pconnstr,
+		'--database' => 'postgres',
+		'--logdir' => $logdir,
+	],
+	'check for log file creation for pg_createSubscriber');
+
+# Check that the log files were created
+my @server_log_files = glob "$logdir*/pg_createsubscriber_server.log";
+is( scalar(@server_log_files), 1, "
+    pg_createsubscriber_server.log file was created");
+my @internal_log_files = glob "$logdir*/pg_createsubscriber_internal.log";
+is( scalar(@internal_log_files), 1, "
+    pg_createsubscriber_internal.log file was created");
+
 # clean up
 $node_p->teardown_node;
 $node_s->teardown_node;
 $node_t->teardown_node;
 $node_f->teardown_node;
+$node_r->teardown_node;
 
 done_testing();
-- 
2.43.0