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Posted to commits@hbase.apache.org by dm...@apache.org on 2012/04/11 14:20:22 UTC
svn commit: r1324730 - in /hbase/trunk/src/docbkx: book.xml configuration.xml
Author: dmeil
Date: Wed Apr 11 12:20:22 2012
New Revision: 1324730
URL: http://svn.apache.org/viewvc?rev=1324730&view=rev
Log:
hbase-5764 adding turning off SpecEx in Config chapter recommendations
Modified:
hbase/trunk/src/docbkx/book.xml
hbase/trunk/src/docbkx/configuration.xml
Modified: hbase/trunk/src/docbkx/book.xml
URL: http://svn.apache.org/viewvc/hbase/trunk/src/docbkx/book.xml?rev=1324730&r1=1324729&r2=1324730&view=diff
==============================================================================
--- hbase/trunk/src/docbkx/book.xml (original)
+++ hbase/trunk/src/docbkx/book.xml Wed Apr 11 12:20:22 2012
@@ -1253,6 +1253,8 @@ if (!b) {
map-tasks which will double-write your data to HBase; this is probably
not what you want.
</para>
+ <para>See <xref linkend="spec.ex"/> for more information.
+ </para>
</section>
</chapter> <!-- mapreduce -->
Modified: hbase/trunk/src/docbkx/configuration.xml
URL: http://svn.apache.org/viewvc/hbase/trunk/src/docbkx/configuration.xml?rev=1324730&r1=1324729&r2=1324730&view=diff
==============================================================================
--- hbase/trunk/src/docbkx/configuration.xml (original)
+++ hbase/trunk/src/docbkx/configuration.xml Wed Apr 11 12:20:22 2012
@@ -1585,6 +1585,13 @@ of all regions.
<para>For more information about compactions and the compaction file selection process, see <xref linkend="compaction"/></para>
</section>
+ <section xml:id="spec.ex"><title>Speculative Execution</title>
+ <para>Speculative Execution of MapReduce tasks is on by default, and for HBase clusters it is generally advised to turn off
+ Speculative Execution at a system-level unless you need it for a specific case, where it can be configured per-job.
+ Set the properties <varname>mapred.map.tasks.speculative.execution</varname> and
+ <varname>mapred.reduce.tasks.speculative.execution</varname> to false.
+ </para>
+ </section>
</section>
<section xml:id="other_configuration"><title>Other Configurations</title>
@@ -1602,6 +1609,7 @@ of all regions.
on the size you need by surveying regionserver UIs; you'll see index block size accounted near the
top of the webpage).</para>
</section>
+
</section>
</section> <!-- important config -->