Mithun Radhakrishnan created HIVE-18608:
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Summary: ORC should allow selectively disabling
dictionary-encoding on specified columns
Key: HIVE-18608
URL: https://issues.apache.org/jira/browse/HIVE-18608
Project: Hive
Issue Type: New Feature
Components: ORC
Affects Versions: 3.0.0, 2.4.0, 2.2.1
Reporter: Mithun Radhakrishnan
Assignee: Mithun Radhakrishnan
Just as ORC allows the choice of columns to enable bloom-filters on, it would
be nice to have a way to specify which columns {{DICTIONARY_V2}} encoding
should be disabled on.
Currently, the choice of dictionary-encoding depends on the results of sampling
the first row-stride within a stripe. If the user knows that a column's
cardinality is bound to prevent an effective dictionary, she might choose to
simply disable it on just that column, and avoid the cost of sampling in the
first row-stride.
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