Author: ddas
Date: Thu Mar 19 11:47:02 2009
New Revision: 755938
URL: http://svn.apache.org/viewvc?rev=755938&view=rev
Log:
HADOOP-5522. Documents the setup/cleanup tasks in the mapred tutorial.
Contributed by Amareshwari Sriramadasu.
Modified:
hadoop/core/trunk/CHANGES.txt
hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml
Modified: hadoop/core/trunk/CHANGES.txt
URL:
http://svn.apache.org/viewvc/hadoop/core/trunk/CHANGES.txt?rev=755938&r1=755937&r2=755938&view=diff
==============================================================================
--- hadoop/core/trunk/CHANGES.txt (original)
+++ hadoop/core/trunk/CHANGES.txt Thu Mar 19 11:47:02 2009
@@ -1102,6 +1102,9 @@
HADOOP-5259. Job with output hdfs:/user/<username>/outputpath (no
authority) fails with Wrong FS. (Doug Cutting via hairong)
+ HADOOP-5522. Documents the setup/cleanup tasks in the mapred tutorial.
+ (Amareshwari Sriramadasu via ddas)
+
Release 0.19.1 - 2009-02-23
IMPROVEMENTS
Modified:
hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml
URL:
http://svn.apache.org/viewvc/hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml?rev=755938&r1=755937&r2=755938&view=diff
==============================================================================
---
hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml
(original)
+++
hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml
Thu Mar 19 11:47:02 2009
@@ -1611,13 +1611,20 @@
Setup the job during initialization. For example, create
the temporary output directory for the job during the
initialization of the job.
+ Job setup is done by a separate task when the job is
+ in PREP state and after initializing tasks. Once the setup task
+ completes, the job will be moved to RUNNING state.
</li>
<li>
Cleanup the job after the job completion. For example, remove the
temporary output directory after the job completion.
+ Job cleanup is done by a separate task at the end of the job.
+ Job is declared SUCCEDED/FAILED/KILLED after the cleanup
+ task completes.
</li>
<li>
Setup the task temporary output.
+ Task setup is done as part of the same task, during task
initialization.
</li>
<li>
Check whether a task needs a commit. This is to avoid the commit
@@ -1625,13 +1632,20 @@
</li>
<li>
Commit of the task output.
+ Once task is done, the task will commit it's output if required.
</li>
<li>
Discard the task commit.
+ If the task has been failed/killed, the output will be cleaned-up.
+ If task could not cleanup (in exception block), a separate task
+ will be launched with same attempt-id to do the cleanup.
</li>
</ol>
<p><code>FileOutputCommitter</code> is the default
- <code>OutputCommitter</code>.</p>
+ <code>OutputCommitter</code>. Job setup/cleanup tasks occupy
+ map or reduce slots, whichever is free on the TaskTracker. And
+ JobCleanup task, TaskCleanup tasks and JobSetup task have the highest
+ priority, and in that order.</p>
</section>
<section>
