// generate the meta data for key
// index for key is -1
TableDesc keyTableDesc = conf.getKeyTblDesc();
SerDe keySerializer = (SerDe) ReflectionUtils.newInstance(keyTableDesc.getDeserializerClass(),
null);
keySerializer.initialize(null, keyTableDesc.getProperties());
MapJoinMetaData.put(Integer.valueOf(metadataKeyTag), new HashTableSinkObjectCtx(
ObjectInspectorUtils.getStandardObjectInspector(keySerializer.getObjectInspector(),
ObjectInspectorCopyOption.WRITABLE), keySerializer, keyTableDesc, hconf));
// index for values is just alias