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From "Zheng Shao (JIRA)" <>
Subject [jira] Updated: (HIVE-553) Add BinarySortableSerDe to Hive
Date Thu, 09 Jul 2009 01:52:15 GMT


Zheng Shao updated HIVE-553:

    Attachment: HIVE-553.3.patch

Removed the support of Map type.
We didn't find a good way to define the order of map type, so we removed the support of map
type in BinarySortableSerDe.

This does not affect any existing functionality of hive, since we never allow order by, group
by, and join on a map-type column.

> Add BinarySortableSerDe to Hive
> -------------------------------
>                 Key: HIVE-553
>                 URL:
>             Project: Hadoop Hive
>          Issue Type: New Feature
>    Affects Versions: 0.3.0, 0.3.1
>            Reporter: Zheng Shao
>            Assignee: Zheng Shao
>         Attachments: HIVE-553.2.patch, HIVE-553.3.patch
> Currently the most popular SerDe in Hive is LazySimpleSerDe. LazySimpleSerDe has the
benefit of being simple (use text format to store data), but its performance may suffer in
the following cases:
> 1. For double values, we are storing them in text format which is very space-inefficient,
and both serialization and deserialization are slow;
> 2. For complex type of columns that contains a lot of levels, we are scanning the buffer
once per level, which is very inefficient.
> We should add a binary serde format that stores the data in binary format. The format
should have the following properties:
> 1. Compact: it should be space-efficient;
> 2. Fast: it should be efficiently to deserialize the data, especially for double values
and complex types.
> 3. It should support serializing NULL values.

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