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https://issues.apache.org/jira/browse/HIVE-11981?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15001026#comment-15001026
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Matt McCline commented on HIVE-11981:
-------------------------------------
Thanks [~omalley]. I added schemaTypes to Reader.Options and segregated the
ORC Hive related stuff like examining configuration variables into the
OrcFileFormat and related classes. When RecordReaderImpl gets the schemaTypes
it then does validation against the actual fileTypes to make sure the schema
evolution is ok. Then, internally, it forms a TreeReaderSchema object to
direct TreeReaderFactory on how to create the tree readers.
> ORC Schema Evolution Issues (Vectorized, ACID, and Non-Vectorized)
> ------------------------------------------------------------------
>
> Key: HIVE-11981
> URL: https://issues.apache.org/jira/browse/HIVE-11981
> Project: Hive
> Issue Type: Bug
> Components: Hive, Transactions
> Reporter: Matt McCline
> Assignee: Matt McCline
> Priority: Critical
> Attachments: HIVE-11981.01.patch, HIVE-11981.02.patch,
> HIVE-11981.03.patch, HIVE-11981.05.patch, HIVE-11981.06.patch,
> HIVE-11981.07.patch, HIVE-11981.08.patch, HIVE-11981.09.patch,
> HIVE-11981.091.patch, HIVE-11981.092.patch, HIVE-11981.093.patch,
> HIVE-11981.094.patch, HIVE-11981.095.patch, HIVE-11981.096.patch,
> HIVE-11981.097.patch, HIVE-11981.098.patch, ORC Schema Evolution Issues.docx
>
>
> High priority issues with schema evolution for the ORC file format.
> Schema evolution here is limited to adding new columns and a few cases of
> column type-widening (e.g. int to bigint).
> Renaming columns, deleting column, moving columns and other schema evolution
> were not pursued due to lack of importance and lack of time. Also, it
> appears a much more sophisticated metadata would be needed to support them.
> The biggest issues for users have been adding new columns for ACID table
> (HIVE-11421 Support Schema evolution for ACID tables) and vectorization
> (HIVE-10598 Vectorization borks when column is added to table).
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