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  1. ORC
  2. ORC-397

ORC should allow selectively disabling dictionary-encoding on specified columns

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Details

    • New Feature
    • Status: Closed
    • Major
    • Resolution: Fixed
    • None
    • 1.5.3, 1.6.0
    • None
    • None

    Description

      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.

      Attachments

        1. HIVE-18608.1-branch-2.2.patch
          10 kB
          Mithun Radhakrishnan
        2. HIVE-18608.2-branch-2.2.patch
          10 kB
          Mithun Radhakrishnan

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            mithun Mithun Radhakrishnan
            mithun Mithun Radhakrishnan
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