@Explain(displayName = "partition key type", explainLevels = { Level.USER, Level.DEFAULT, Level.EXTENDED })
  public String getPartKeyType() {
    return partKeySpec.getType();
  }
DDL task description for ALTER TABLE ... PARTITION COLUMN ... commands.
ql/src/java/org/apache/hadoop/hive/ql/ddl/table/partition/alter/AlterTableAlterPartitionDesc.java