MAPREDUCE-6795. Update the document for JobConf#setNumReduceTasks. Contributed by Yiqun Lin.
Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/235f39b7 Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/235f39b7 Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/235f39b7 Branch: refs/heads/YARN-5355 Commit: 235f39b7c44c5907bd4de063892905577c35cd80 Parents: 9d0c2ad Author: Akira Ajisaka <aajis...@apache.org> Authored: Tue Nov 1 20:51:35 2016 +0900 Committer: Akira Ajisaka <aajis...@apache.org> Committed: Tue Nov 1 20:52:12 2016 +0900 ---------------------------------------------------------------------- .../src/main/java/org/apache/hadoop/mapred/JobConf.java | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hadoop/blob/235f39b7/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/JobConf.java ---------------------------------------------------------------------- diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/JobConf.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/JobConf.java index f2b0aae..85b4c93 100644 --- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/JobConf.java +++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/JobConf.java @@ -1347,9 +1347,14 @@ public class JobConf extends Configuration { * <b id="NoOfReduces">How many reduces?</b> * * <p>The right number of reduces seems to be <code>0.95</code> or - * <code>1.75</code> multiplied by (<<i>no. of nodes</i>> * - * <a href="{@docRoot}/../mapred-default.html#mapreduce.tasktracker.reduce.tasks.maximum"> - * mapreduce.tasktracker.reduce.tasks.maximum</a>). + * <code>1.75</code> multiplied by ( + * <i>available memory for reduce tasks</i> + * (The value of this should be smaller than + * numNodes * yarn.nodemanager.resource.memory-mb + * since the resource of memory is shared by map tasks and other + * applications) / + * <a href="{@docRoot}/../hadoop-mapreduce-client/hadoop-mapreduce-client-core/mapred-default.xml#mapreduce.reduce.memory.mb"> + * mapreduce.reduce.memory.mb</a>). * </p> * * <p>With <code>0.95</code> all of the reduces can launch immediately and --------------------------------------------------------------------- To unsubscribe, e-mail: common-commits-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-commits-h...@hadoop.apache.org
