There exists structures for supporting this in the metastore, but that feature isn't in Hive yet. For example, although the metadata for partitions include its own set of columns, parts of the code in the query processor still read from table level metadata.
Some evolution can occur in the form of adding columns to a table.
Sent: Thursday, July 01, 2010 4:43 PM
Subject: Schema evolution?
I read on the VLBD hive paper "Hive - A Warehousing Solution Over a
that Partitions could have different schemas : (section 3.1 MetaStore) "
Partition - Each partition can have its own columns
and SerDe and storage information. This can be used
in the future to support schema evolution in a Hive
but the API:
only lists getSchema() for Table, and Partition does not have a
is the schema evolution feature really there?