Pig and Hive cannot read repeated groups written with parquet-protobuf

parquet-hive and parquet-pig make assumptions about list schemas that are not compatible with the more compact schemas generated by parquet-protobuf. This bug was discussed in more detail on https://github.com/Parquet/parquet-mr/issues/354

**Reporter**: [Nathan Howell](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=NathanHowell)

_{**Note**: *This issue was originally created as [PARQUET-14](https://issues.apache.org/jira/browse/PARQUET-14). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Inizia leggendo la gestione di list-schema in parquet-hive e parquet-pig, quindi usa la discussione nell’issue 354 per capire come parquet-protobuf produca schemi compatti di repeated-group. Il lavoro è completato quando entrambi i reader accettano questi schemi senza rompere la gestione esistente di list-schema; il contenuto non indica file o test specifici, quindi questi entry point devono essere individuati per primi.

Scritto dal modello di indicizzazione a partire dal testo della issue.