Parquet file containing arrays, written by Parquet-MR, cannot be read again by Parquet-MR
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Descripción
In the attached files, there is one original file, and one written modified file that results after reading the original file and writing it back with Parquet-MR, with a few values modified. The schema should not be modified, since the schema of the input file is used as the schema to write the output file. However, the output file has a slightly modified schema that then cannot be read back the same way again with Parquet-MR, resulting in the exception message: java.lang.ClassCastException: optional binary element (STRING) is not a group
My guess is that the issue lies in the Avro schema conversion.
The Parquet files attached have some arrays and some nested fields.
**Environment**: Windows 10
**Reporter**: [Devon Kozenieski](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=devonk)
#### Related issues:
- [parquet schema conflict: optional binary (UTF8) is not a group](https://issues.apache.org/jira/browse/HUDI-864) (is depended upon by)
#### Original Issue Attachments:
- [modified.parquet](https://issues.apache.org/jira/secure/attachment/13030885/modified.parquet)
- [original.parquet](https://issues.apache.org/jira/secure/attachment/13030884/original.parquet)
- [parquet-diff.png](https://issues.apache.org/jira/secure/attachment/13042124/parquet-diff.png)
**Note**: *This issue was originally created as [PARQUET-2069](https://issues.apache.org/jira/browse/PARQUET-2069). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*
Guía de contribución
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Línea de trabajo
Comienza comparando los archivos adjuntos original.parquet y modified.parquet; después, rastrea la conversión del esquema Avro que se utiliza cuando Parquet-MR lee y vuelve a escribir arrays anidados. Reproduce la ClassCastException al leer el archivo reescrito; el trabajo estará terminado cuando el esquema siga siendo compatible y Parquet-MR pueda volver a leer la salida.
Escrito por el modelo de indexación a partir del texto del issue.
Evaluación
- Stack tecnológico
- java
- Área
- data-engineering
- Tipo de issue
- Error
- Dificultad
- 4/5
- Tiempo estimado
- 3-5 días
- Estado de actividad
- Estancado
- Claridad
- Bastante claro
- Aptitud para principiantes
- 35/100