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From "Aaron Kimball (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HADOOP-5844) Use mysqldump when connecting to local mysql instance in Sqoop
Date Tue, 26 May 2009 17:39:45 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-5844?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Aaron Kimball updated HADOOP-5844:
----------------------------------

    Status: Patch Available  (was: Open)

Cycling the patch status now that 5815 is in to actually test this

> Use mysqldump when connecting to local mysql instance in Sqoop
> --------------------------------------------------------------
>
>                 Key: HADOOP-5844
>                 URL: https://issues.apache.org/jira/browse/HADOOP-5844
>             Project: Hadoop Core
>          Issue Type: New Feature
>            Reporter: Aaron Kimball
>            Assignee: Aaron Kimball
>         Attachments: mysqldump.patch
>
>
> Sqoop uses MapReduce + DBInputFormat to read the contents of a table into HDFS. On many
databases, this implementation is O(N^2) in the number of rows. Also, the use of multiple
mappers has low value in terms of throughput, because the database itself is inherently singlethreaded.
While DBInputFormat/JDBC provides a useful fallback mechanism for importing from databases,
db-specific dump utilities will nearly always provide faster throughput, and should be selected
when available. This patch allows users to use mysqldump to read from local mysql instances
instead of the MapReduce-based input.
> If you provide sqoop with arguments of the form " --connect jdbc:mysql://localhost/somedatabase
--local", it will use the mysqldump fast path to perform the import.
> This patch, naturally, requires that MySQL be installed on a machine to test it. Thus
the test that this adds is called LocalMySQLTest (instead of the Hadoop-preferred file naming,
TestLocalMySQL) so that Hudson doesn't automatically run it. You can run this test yourself
by using "ant -Dtestcase=LocalMySQLTest test". See the notes in the javadoc for the LocalMySQLTest
class in how to set up the MySQL test environment for this.

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