private Partition alterPartitionNoTxn(String catName, String dbname, String name,
      List<String> part_vals, Partition newPart, String validWriteIds, Ref<MColumnDescriptor> oldCd)
      throws InvalidObjectException, MetaException {
    MTable table = this.getMTable(newPart.getCatName(), newPart.getDbName(), newPart.getTableName());
    MPartition oldp = getMPartition(catName, dbname, name, part_vals, table);
    return alterPartitionNoTxn(catName, dbname, name, oldp, newPart,
        validWriteIds, oldCd, table);
  }
Alters an existing partition. Initiates copy of SD. Returns the old CD.
@param part_vals Partition values (of the original partition instance)
@param newPart Partition object containing new information
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java