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From "Aaron Kimball (JIRA)" <j...@apache.org>
Subject [jira] Updated: (MAPREDUCE-1224) Calling "SELECT t.* from <table> AS t" to get meta information is too expensive for big tables
Date Sat, 28 Nov 2009 01:07:20 GMT

     [ https://issues.apache.org/jira/browse/MAPREDUCE-1224?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Aaron Kimball updated MAPREDUCE-1224:
-------------------------------------

    Hadoop Flags: [Reviewed]

> Calling "SELECT t.* from <table> AS t" to get meta information is too expensive
for big tables
> ----------------------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-1224
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1224
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: contrib/sqoop
>    Affects Versions: 0.20.1
>         Environment: all platforms, generic jdbc driver
>            Reporter: Spencer Ho
>         Attachments: MAPREDUCE-1224.patch, SqlManager.java
>
>
> The SqlManager uses the query, "SELECT t.* from <table> AS t" to get table spec
is too expensive for big tables, and it was called twice to generate column names and types.
 For tables that are big enough to be map-reduced, this is too expensive to make sqoop useful.

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