svn commit: r549268 - in /lucene/hadoop/trunk: CHANGES.txt src/java/org/apache/hadoop/dfs/DataNode.java

[cu...@apache.org]

Author: cutting
Date: Wed Jun 20 14:58:17 2007
New Revision: 549268

URL: http://svn.apache.org/viewvc?view=rev&rev=549268
Log:
HADOOP-1501.  Better randomize sending of block reports to namenode.  Contributed by Dhruba.

Modified:
    lucene/hadoop/trunk/CHANGES.txt
    lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DataNode.java

Modified: lucene/hadoop/trunk/CHANGES.txt
URL: http://svn.apache.org/viewvc/lucene/hadoop/trunk/CHANGES.txt?view=diff&rev=549268&r1=549267&r2=549268
==============================================================================
--- lucene/hadoop/trunk/CHANGES.txt (original)
+++ lucene/hadoop/trunk/CHANGES.txt Wed Jun 20 14:58:17 2007
@@ -223,6 +223,9 @@
  67. HADOOP-1455.  Permit specification of arbitrary job options on
      pipes command line.  (Devaraj Das via cutting)
 
+ 68. HADOOP-1501.  Better randomize sending of block reports to
+     namenode, so reduce load spikes.  (Dhruba Borthakur via cutting)
+
 
 Release 0.13.0 - 2007-06-08
 

Modified: lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DataNode.java
URL: http://svn.apache.org/viewvc/lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DataNode.java?view=diff&rev=549268&r1=549267&r2=549268
==============================================================================
--- lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DataNode.java (original)
+++ lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DataNode.java Wed Jun 20 14:58:17 2007
@@ -483,7 +483,15 @@
           //
           DatanodeCommand cmd = namenode.blockReport(dnRegistration,
                                                      data.getBlockReport());
-          lastBlockReport = now;
+          //
+          // If we have sent the first block report, then wait a random
+          // time before we start the periodic block reports.
+          //
+          if (lastBlockReport == 0) {
+            lastBlockReport = now - new Random().nextInt((int)(blockReportInterval));
+          } else {
+            lastBlockReport = now;
+          }
           processCommand(cmd);
         }