private long getSyncedPosition() throws IOException {
    return recordReader.getPos();
  }
When start reading new file, check header, footer rows.
If file contains header, skip header lines before reading the records.
If file contains footer, used a FooterBuffer to remove footer lines
at the end of the table file.
ql/src/java/org/apache/hadoop/hive/ql/io/HiveContextAwareRecordReader.java