@Override
  public void alter_table(String catName, String dbName, String tblName, Table newTable,
                         EnvironmentContext envContext) throws TException {
    // This never used to call the hook. Why? There's overload madness in metastore...
    AlterTableRequest req = new AlterTableRequest(dbName, tblName, newTable);
    req.setCatName(catName);
    req.setEnvironmentContext(envContext);
    if (processorCapabilities != null) {
      req.setProcessorCapabilities(new ArrayList<String>(Arrays.asList(processorCapabilities)));
      req.setProcessorIdentifier(processorIdentifier);
    }
    client.alter_table_req(req);
  }
Swaps the first element of the metastoreUris array with a random element from the
remainder of the array.
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/HiveMetaStoreClient.java