From 6fa8f6a0423eecc9327e71a8a50cf5d1a1ccf845 Mon Sep 17 00:00:00 2001
From: Jean-Daniel Cryans <jdcryans@apache.org>
Date: Fri, 17 Feb 2012 19:56:54 +0000
Subject: [PATCH] HBASE-4640  Catch ClosedChannelException and document it

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1245730 13f79535-47bb-0310-9956-ffa450edef68
---
 src/docbkx/troubleshooting.xml                        | 11 ++++++++++-
 .../java/org/apache/hadoop/hbase/ipc/HBaseServer.java |  5 +++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/docbkx/troubleshooting.xml b/src/docbkx/troubleshooting.xml
index e6c216ec687..a92d9794e92 100644
--- a/src/docbkx/troubleshooting.xml
+++ b/src/docbkx/troubleshooting.xml
@@ -888,7 +888,7 @@ ERROR org.apache.hadoop.hbase.regionserver.HRegionServer: ZooKeeper session expi
            as forward lookup. See <link xlink:href="https://issues.apache.org/jira/browse/HBASE-3431">HBASE 3431
            RegionServer is not using the name given it by the master; double entry in master listing of servers</link> for gorey details.
           </para>
-          </section>
+        </section>
         <section xml:id="trouble.rs.runtime.codecmsgs">
           <title>Logs flooded with '2011-01-10 12:40:48,407 INFO org.apache.hadoop.io.compress.CodecPool: Got
             brand-new compressor' messages</title>
@@ -898,6 +898,15 @@ ERROR org.apache.hadoop.hbase.regionserver.HRegionServer: ZooKeeper session expi
                     symlink them into place and the message should go away.
                 </para>
         </section>
+        <section xml:id="trouble.rs.runtime.client_went_away">
+           <title>Server handler X on 60020 caught: java.nio.channels.ClosedChannelException</title>
+           <para>
+           If you see this type of message it means that the region server was trying to read/send data from/to a client but
+           it already went away. Typical causes for this are if the client was killed (you see a storm of messages like this when a MapReduce
+           job is killed or fails) or if the client receives a SocketTimeoutException. It's harmless, but you should consider digging in
+           a bit more if you aren't doing something to trigger them.
+           </para>
+        </section>
 
       </section>    
       <section xml:id="trouble.rs.shutdown">
diff --git a/src/main/java/org/apache/hadoop/hbase/ipc/HBaseServer.java b/src/main/java/org/apache/hadoop/hbase/ipc/HBaseServer.java
index dbc4b34f84d..5e004042645 100644
--- a/src/main/java/org/apache/hadoop/hbase/ipc/HBaseServer.java
+++ b/src/main/java/org/apache/hadoop/hbase/ipc/HBaseServer.java
@@ -1378,6 +1378,11 @@ public abstract class HBaseServer implements RpcServer {
             // rethrow if no handler
             throw e;
           }
+       } catch (ClosedChannelException cce) {
+          LOG.warn(getName() + " caught a ClosedChannelException, " +
+            "this means that the server was processing a " +
+            "request but the client went away. The error message was: " +
+            cce.getMessage());
         } catch (Exception e) {
           LOG.warn(getName() + " caught: " +
                    StringUtils.stringifyException(e));