bugfix: correctly calculate wal-bytes for STREAM backups

Author: gsmolk

src/backup.c

@@ -642,10 +642,15 @@ do_backup_instance(PGconn *backup_conn, PGNodeInfo *nodeInfo, bool no_sync, bool
 			 */
 			pg_free(file->rel_path);
 
+			/* Now it is relative to /backup_dir/backups/instance_name/backup_id/database/ */
 			file->rel_path = pgut_strdup(GetRelativePath(wal_full_path, database_path));
+
 			file->name = last_dir_separator(file->rel_path);
 
-			/* Now it is relative to /backup_dir/backups/instance_name/backup_id/database/ */
+			if (file->name == NULL)
+				file->name = file->rel_path;
+			else
+				file->name++;
 		}
 
 		/* Add xlog files into the list of backed up files */

src/catalog.c

@@ -1880,7 +1880,7 @@ write_backup_filelist(pgBackup *backup, parray *files, const char *root,
 			 * Size of WAL files in 'pg_wal' is counted separately
 			 * TODO: in 3.0 add attribute is_walfile
 			 */
-			if (IsXLogFileName(file->name) && (file->external_dir_num == 0))
+			if (IsXLogFileName(file->name) && file->external_dir_num == 0)
 				wal_size_on_disk += file->write_size;
 			else
 			{

src/data.c

@@ -2230,6 +2230,8 @@ get_data_file_headers(HeaderMap *hdr_map, pgFile *file, uint32 backup_version, b
 	return headers;
 }
 
+/* write headers of all blocks belonging to file to header map and
+ * save its offset and size */
 void
 write_page_headers(BackupPageHeader2 *headers, pgFile *file, HeaderMap *hdr_map, bool is_merge)
 {