From 56c76ceb86a4e3c72e5cbde516d55db41f1633a9 Mon Sep 17 00:00:00 2001
From: Mike Copley <mikec@makonetworks.com>
Date: Tue, 14 Dec 2010 14:58:52 +0000
Subject: [PATCH] Added support for ping ceiling to ReplicaSetStatus

---
 src/main/com/mongodb/DBTCPConnector.java   |    4 ++--
 src/main/com/mongodb/MongoOptions.java     |    8 ++++++++
 src/main/com/mongodb/ReplicaSetStatus.java |    9 +++++----
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/main/com/mongodb/DBTCPConnector.java b/src/main/com/mongodb/DBTCPConnector.java
index a5e64ef..7aff8bc 100644
--- a/src/main/com/mongodb/DBTCPConnector.java
+++ b/src/main/com/mongodb/DBTCPConnector.java
@@ -39,7 +39,7 @@ class DBTCPConnector implements DBConnector {
 
         if ( addr.isPaired() ){
             _allHosts = new ArrayList<ServerAddress>( addr.explode() );
-            _rsStatus = new ReplicaSetStatus( _allHosts );
+            _rsStatus = new ReplicaSetStatus( _allHosts, m._options );
             _createLogger.info( "switching to replica set mode : " + _allHosts + " -> " + _curMaster  );
         }
         else {
@@ -61,7 +61,7 @@ class DBTCPConnector implements DBConnector {
         _checkAddress( all );
 
         _allHosts = new ArrayList<ServerAddress>( all ); // make a copy so it can't be modified
-        _rsStatus = new ReplicaSetStatus( _allHosts );
+        _rsStatus = new ReplicaSetStatus( _allHosts, m._options );
 
         _createLogger.info( all  + " -> " + _curMaster );
     }
diff --git a/src/main/com/mongodb/MongoOptions.java b/src/main/com/mongodb/MongoOptions.java
index b8a0d3d..6cc9b2b 100644
--- a/src/main/com/mongodb/MongoOptions.java
+++ b/src/main/com/mongodb/MongoOptions.java
@@ -36,6 +36,7 @@ public class MongoOptions {
         connectTimeout = 0;
         socketTimeout = 0;
         autoConnectRetry = false;
+        slaveRandomSelectionPingCeiling = 200;
     }
 
     /**
@@ -72,6 +73,12 @@ public class MongoOptions {
     */
     public boolean autoConnectRetry;
     
+    /**
+       The max ping time, in milliseconds, a slave can have to be randomly selected when using slaveOK. Defaults to 200ms.
+       A slave above this ceiling will still be used if no other slave node has a quicker ping time.
+     */
+    public long slaveRandomSelectionPingCeiling;
+    
     public String toString(){
         StringBuilder buf = new StringBuilder();
         buf.append( "connectionsPerHost: " ).append( connectionsPerHost ).append( " " );
@@ -80,6 +87,7 @@ public class MongoOptions {
         buf.append( "connectTimeout: " ).append( connectTimeout ).append( " " );
         buf.append( "socketTimeout: " ).append( socketTimeout ).append( " " );
         buf.append( "autoConnectRetry: " ).append( autoConnectRetry ).append( " " );
+        buf.append( "slaveRandomSelectionPingCeiling: " ).append( slaveRandomSelectionPingCeiling ).append( " " );
         return buf.toString();
     }
     
diff --git a/src/main/com/mongodb/ReplicaSetStatus.java b/src/main/com/mongodb/ReplicaSetStatus.java
index dc41895..c368d0b 100644
--- a/src/main/com/mongodb/ReplicaSetStatus.java
+++ b/src/main/com/mongodb/ReplicaSetStatus.java
@@ -21,8 +21,8 @@ class ReplicaSetStatus {
 
     static final Logger _rootLogger = Logger.getLogger( "com.mongodb.ReplicaSetStatus" );
     
-    ReplicaSetStatus( List<ServerAddress> initial ){
-        
+    ReplicaSetStatus( List<ServerAddress> initial, MongoOptions options ){
+    	_options = options;
         _all = Collections.synchronizedList( new ArrayList<Node>() );
         for ( ServerAddress addr : initial ){
             _all.add( new Node( addr ) );
@@ -91,7 +91,7 @@ class ReplicaSetStatus {
             long diff = best._pingTime - n._pingTime;
             if ( diff > 15 || 
                  // this is a complex way to make sure we get a random distribution of slaves
-                 ( ( badBeforeBest - mybad ) / ( _all.size() - 1 ) ) > _random.nextDouble() ) 
+                 ( diff < _options.slaveRandomSelectionPingCeiling && ( ( badBeforeBest - mybad ) / ( _all.size() - 1 ) ) > _random.nextDouble() ) ) 
                 { 
                 best = n;
                 badBeforeBest = mybad;
@@ -324,6 +324,7 @@ class ReplicaSetStatus {
     }
 
 
+    final MongoOptions _options;
     final List<Node> _all;
     Updater _updater;
     String _setName = null; // null until init
@@ -350,7 +351,7 @@ class ReplicaSetStatus {
 
         Mongo m = new Mongo( addrs );
 
-        ReplicaSetStatus status = new ReplicaSetStatus( addrs );
+        ReplicaSetStatus status = new ReplicaSetStatus( addrs, m._options );
         System.out.println( status.ensureMaster()._addr );
 
         while ( true ){
-- 
1.7.3.2