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https://issues.apache.org/jira/browse/SPARK-25175?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Apache Spark reassigned SPARK-25175:
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Assignee: (was: Apache Spark)
> Field resolution should fail if there's ambiguity for ORC native reader
> -----------------------------------------------------------------------
>
> Key: SPARK-25175
> URL: https://issues.apache.org/jira/browse/SPARK-25175
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.3.1
> Reporter: Chenxiao Mao
> Priority: Major
>
> SPARK-25132 adds support for case-insensitive field resolution when reading
> from Parquet files. We found ORC files have similar issues, but not identical
> to Parquet. Spark has two OrcFileFormat.
> * Since SPARK-2883, Spark supports ORC inside sql/hive module with Hive
> dependency. This hive OrcFileFormat always do case-insensitive field
> resolution regardless of case sensitivity mode. When there is ambiguity, hive
> OrcFileFormat always returns the first matched field, rather than failing the
> reading operation.
> * SPARK-20682 adds a new ORC data source inside sql/core. This native
> OrcFileFormat supports case-insensitive field resolution, however it cannot
> handle duplicate fields.
> Besides data source tables, hive serde tables also have issues. If ORC data
> file has more fields than table schema, we just can't read hive serde tables.
> If ORC data file does not have more fields, hive serde tables always do field
> resolution by ordinal, rather than by name.
> Both ORC data source hive impl and hive serde table rely on the hive orc
> InputFormat/SerDe to read table. I'm not sure whether we can change
> underlying hive classes to make all orc read behaviors consistent.
> This ticket aims to make read behavior of ORC data source native impl
> consistent with Parquet data source.
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