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From "Spencer Ho (JIRA)" <j...@apache.org>
Subject [jira] Created: (MAPREDUCE-1224) Calling "SELECT t.* from <table> AS t" to get meta information is too expensive for big tables
Date Fri, 20 Nov 2009 00:32:39 GMT
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


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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