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From "Zheng Shao (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-266) Improve SerDe performance by using Text instead of String
Date Mon, 16 Feb 2009 22:30:02 GMT

    [ https://issues.apache.org/jira/browse/HIVE-266?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12674074#action_12674074

Zheng Shao commented on HIVE-266:

HIVE-270 LazySimpleSerDe avoids String.split() but it still creates a String object per column
per row.

Also we will need to write routines for LazySimpleSerDe to directly serialize (append) int/long/byte/short
etc to UTF-8 buffer.

> Improve SerDe performance by using Text instead of String
> ---------------------------------------------------------
>                 Key: HIVE-266
>                 URL: https://issues.apache.org/jira/browse/HIVE-266
>             Project: Hadoop Hive
>          Issue Type: Improvement
>          Components: Serializers/Deserializers
>    Affects Versions: 0.2.0
>            Reporter: Zheng Shao
>            Priority: Critical
> A recent performance study showed that 2 places in Hive code has exhibited large cpu
usage percentage:
> 1. String.getBytes() (UTF-8 encoding)
> 2. String.split()
> We should replace String with Text object to:
> 1. Avoid UTF-8 decoding and encoding
> 2. Reuse the Text object and avoid creating new objects for each column in each row like
in String.split()
> This is expected to give a big (20%+) performance improvement to Hive.

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