@Override
  protected void doAlteration(Table table, Partition partition) throws HiveException {
    // Validation's been done at compile time. no validation is needed here.
    // Convert skewed table to non-skewed table.
    if (table.getSkewedInfo() == null) {
      table.setSkewedInfo(new SkewedInfo());
    }
    table.setSkewedColNames(new ArrayList<String>());
    table.setSkewedColValues(new ArrayList<List<String>>());

    table.setStoredAsSubDirectories(false);
  }
Operation process of turning of skewing.
ql/src/java/org/apache/hadoop/hive/ql/ddl/table/storage/skewed/AlterTableNotSkewedOperation.java