Mariano Dominguez created HIVE-7046:
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Summary: Propagate addition of new columns to partition schema
Key: HIVE-7046
URL: https://issues.apache.org/jira/browse/HIVE-7046
Project: Hive
Issue Type: Improvement
Components: Database/Schema
Affects Versions: 0.12.0
Reporter: Mariano Dominguez
Hive reads data according to the partition schema, not the table schema
(because of HIVE-3833). ALTER TABLE only updates the table schema, and the
changes are not propagated to partitions. Thus, the schema of a partition will
differ from that of the table after altering the table schema; this is done to
preserve the ability to read existing data, particularly when using binary
formats such as RCFile. Binary formats do not allow changing the type of a
field because of the way serialization works; a field serialized as a string
will be displayed incorrectly if read as an integer.
Unfortunately, as a side effect, this behavior limits the ability to add new
columns to already exiting partitions using ALTER TABLE ADD COLUMNS. A possible
workaround is to recreate the partitions, but this process could be
unnecessarily cumbersome if the number of partitions is high. New columns
should be propagated to existing partitions automatically instead.
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