[SPARK-25132][SQL] Case-insensitive field resolution when reading from Parquet/ORC #22142
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…uet/ORC * Fix ParquetFileFormat * More than one Parquet column is matched * Fix OrcFileFormat (both native and hive implementations) * Fix issues according to review results: refactor test cases, code style, ... * Test cases: change paruqet/orc file schema from a to A * Test cases: let different columns have different value series * Refine error message * Split multi-format test suite * Simplify test cases for ambiguous resolution * Simplify test cases to reduce code lines * Refine tests and comments
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Can one of the admins verify this patch? |
seancxmao
changed the title
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Split this into 2 PRs, one for Parquet and ORC respectively. |
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What changes were proposed in this pull request?
Spark SQL returns NULL for a column whose Hive metastore schema and Parquet schema are in different letter cases, regardless of spark.sql.caseSensitive set to true or false. This applies not only to Parquet, but also to ORC. Following is a brief summary:
#15799 reverted case-insensitive resolution for ParquetFileFormat and hive OrcFileFormat. This PR brings it back and improves it to do case-insensitive resolution only if Spark is in case-insensitive mode. And field resolution will fail if there is ambiguity, i.e. more than one field is matched. ParquetFileFormat, native OrcFileFormat and hive OrcFileFormat are all supported.
How was this patch tested?
Unit tests added.