HADOOP-1849. Merge -r 916528:916529 from trunk to branch-0.21.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.21@916530 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -1185,6 +1185,11 @@ Release 0.20.2 - 2010-2-10
     HADOOP-6498. IPC client bug may cause rpc call hang. (Ruyue Ma and
     hairong via hairong)
 
+  IMPROVEMENTS
+
+    HADOOP-1849. Add undocumented configuration parameter for per handler 
+    call queue size in IPC Server. (shv)
+
 Release 0.20.1 - 2009-09-01
 
   INCOMPATIBLE CHANGES

src/java/org/apache/hadoop/fs/CommonConfigurationKeys.java

@@ -119,6 +119,16 @@ public class CommonConfigurationKeys {
   public static final int     IPC_CLIENT_IDLETHRESHOLD_DEFAULT = 4000;
   public static final String  IPC_SERVER_TCPNODELAY_KEY = "ipc.server.tcpnodelay";
   public static final boolean IPC_SERVER_TCPNODELAY_DEFAULT = false;
+  /**
+   * How many calls per handler are allowed in the queue.
+   */
+  public static final String  IPC_SERVER_HANDLER_QUEUE_SIZE_KEY = 
+                                       "ipc.server.handler.queue.size";
+  /**
+   * The default number of calls per handler in the queue.
+   */
+  public static final int IPC_SERVER_HANDLER_QUEUE_SIZE_DEFAULT = 100;
+  
 
   public static final String  HADOOP_RPC_SOCKET_FACTORY_CLASS_DEFAULT_KEY = 
                                        "hadoop.rpc.socket.factory.class.default";

src/java/org/apache/hadoop/ipc/Server.java

@@ -60,6 +60,7 @@ import javax.security.auth.Subject;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.CommonConfigurationKeys;
 import org.apache.hadoop.security.SecurityUtil;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableUtils;
@@ -84,12 +85,7 @@ public abstract class Server {
   // 1 : Introduce ping and server does not throw away RPCs
   // 3 : Introduce the protocol into the RPC connection header
   public static final byte CURRENT_VERSION = 3;
-  
-  /**
-   * How many calls/handler are allowed in the queue.
-   */
-  private static final int MAX_QUEUE_SIZE_PER_HANDLER = 100;
-  
+
   /**
    * Initial and max size of response buffer
    */
@@ -1034,7 +1030,9 @@ public abstract class Server {
     this.paramClass = paramClass;
     this.handlerCount = handlerCount;
     this.socketSendBufferSize = 0;
-    this.maxQueueSize = handlerCount * MAX_QUEUE_SIZE_PER_HANDLER;
+    this.maxQueueSize = handlerCount * conf.getInt(
+                CommonConfigurationKeys.IPC_SERVER_HANDLER_QUEUE_SIZE_KEY,
+                CommonConfigurationKeys.IPC_SERVER_HANDLER_QUEUE_SIZE_DEFAULT);
     this.callQueue  = new LinkedBlockingQueue<Call>(maxQueueSize); 
     this.maxIdleTime = 2*conf.getInt("ipc.client.connection.maxidletime", 1000);
     this.maxConnectionsToNuke = conf.getInt("ipc.client.kill.max", 10);