Save and compare system-identifier.

Author: stalkerg

init.c

@@ -34,6 +34,7 @@ do_init(void)
 	char   *log_directory = NULL;
 	char   *archive_command = NULL;
 	FILE   *fp;
+	uint64 _system_identifier;
 
 	struct dirent **dp;
 	int results;
@@ -58,6 +59,7 @@ do_init(void)
 		parse_postgresql_conf(path, &log_directory, &archive_command);
 	}
 
+	_system_identifier = get_system_identifier(false);
 	/* create pg_probackup.conf */
 	join_path_components(path, backup_path, PG_RMAN_INI_FILE);
 	fp = fopen(path, "wt");
@@ -67,6 +69,7 @@ do_init(void)
 	join_path_components(arclog_path_dir, backup_path, "wal");
 	dir_create_dir(arclog_path_dir, DIR_PERMISSION);
 
+	fprintf(fp, "system-identifier = %li\n", _system_identifier);
 	fprintf(fp, "\n");
 	fclose(fp);
 

pg_probackup.c

@@ -40,6 +40,7 @@ bool			from_replica = false;
 static bool		backup_logs = false;
 bool			progress = false;
 bool			delete_wal = false;
+uint64			system_identifier = 0;
 
 /* restore configuration */
 static char		   *target_time;
@@ -74,6 +75,8 @@ static pgut_option options[] =
 	{ 'u',  6, "timeline",				&target_tli,		SOURCE_CMDLINE },
 	/* delete options */
 	{ 'b', 12, "wal",					&delete_wal },
+	/* other */
+	{ 'U', 13, "system-identifier",		&system_identifier,	SOURCE_FILE },
 	{ 0 }
 };
 
@@ -188,10 +191,16 @@ main(int argc, char *argv[])
 	{
 		pgBackupOption bkupopt;
 		int res;
+		uint64 _system_identifier;
 		bkupopt.smooth_checkpoint = smooth_checkpoint;
 		bkupopt.keep_data_generations = keep_data_generations;
 		bkupopt.keep_data_days = keep_data_days;
 
+		_system_identifier = get_system_identifier(true);
+		if (_system_identifier != system_identifier)
+			elog(ERROR, "Backup directory was initialized for system id = %ld, but target system id = %ld",
+				 system_identifier, _system_identifier);
+
 		/* Do the backup */
 		res = do_backup(bkupopt);
 		if (res != 0)

pg_probackup.h

@@ -205,6 +205,7 @@ extern bool stream_wal;
 extern bool from_replica;
 extern bool progress;
 extern bool delete_wal;
+extern uint64 system_identifier;
 
 /* in backup.c */
 extern int do_backup(pgBackupOption bkupopt);
@@ -310,6 +311,7 @@ extern XLogRecPtr get_last_ptrack_lsn(void);
 extern uint32 get_data_checksum_version(bool safe);
 extern char *base36enc(long unsigned int value);
 extern long unsigned int base36dec(const char *text);
+extern uint64 get_system_identifier(bool safe);
 
 /* in status.c */
 extern bool is_pg_running(void);

util.c

@@ -122,6 +122,23 @@ get_current_timeline(bool safe)
 	return ControlFile.checkPointCopy.ThisTimeLineID;
 }
 
+uint64
+get_system_identifier(bool safe)
+{
+	ControlFileData ControlFile;
+	char       *buffer;
+	size_t      size;
+
+	/* First fetch file... */
+	buffer = slurpFile(pgdata, "global/pg_control", &size, safe);
+	if (buffer == NULL)
+		return 0;
+	digestControlFile(&ControlFile, buffer, size);
+	pg_free(buffer);
+
+	return ControlFile.system_identifier;
+}
+
 uint32
 get_data_checksum_version(bool safe)
 {