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Apache Spark commented on SPARK-22329:
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User 'dongjoon-hyun' has created a pull request for this issue:
https://github.com/apache/spark/pull/19552
> Use NEVER_INFER for `spark.sql.hive.caseSensitiveInferenceMode` by default
> --------------------------------------------------------------------------
>
> Key: SPARK-22329
> URL: https://issues.apache.org/jira/browse/SPARK-22329
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.2.0
> Reporter: Dongjoon Hyun
> Priority: Critical
>
> In Spark 2.2.0, `spark.sql.hive.caseSensitiveInferenceMode` has a critical issue.
> - SPARK-19611 uses `INFER_AND_SAVE` at 2.2.0 since Spark 2.1.0 breaks some Hive tables
backed by case-sensitive data files.
> bq. This situation will occur for any Hive table that wasn't created by Spark or that
was created prior to Spark 2.1.0. If a user attempts to run a query over such a table containing
a case-sensitive field name in the query projection or in the query filter, the query will
return 0 results in every case.
> - However, SPARK-22306 reports this also corrupts Hive Metastore schema by removing bucketing
information (BUCKETING_COLS, SORT_COLS) and changing owner.
> - Since Spark 2.3.0 supports Bucketing, BUCKETING_COLS and SORT_COLS look okay at least.
However, we need to figure out the issue of changing owners. Also, we cannot backport bucketing
patch into `branch-2.2`. We need more tests on before releasing 2.3.0.
> Hive Metastore is a shared resource and Spark should not corrupt it by default. This
issue proposes to recover that option back to `NEVER_INFO` like Spark 2.2.0 by default. Users
can take a risk by enabling `INFER_AND_SAVE` by themselves.
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