public Set<TableName> getIncrementalBackupTableSet(String backupRoot) throws IOException {
    LOG.trace("get incremental backup table set from backup system table");

    TreeSet<TableName> set = new TreeSet<>();

    try (Table table = connection.getTable(tableName)) {
      Get get = createGetForIncrBackupTableSet(backupRoot);
      Result res = table.get(get);
      if (res.isEmpty()) {
        return set;
      }
      List<Cell> cells = res.listCells();
      for (Cell cell : cells) {
        // qualifier = table name - we use table names as qualifiers
        set.add(TableName.valueOf(CellUtil.cloneQualifier(cell)));
      }
      return set;
    }
  }
Return the current tables covered by incremental backup.
@param backupRoot root directory path to backup
@return set of tableNames
@throws IOException exception
hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupSystemTable.java