From 1ba0144d4f92ed2a4f97d89ad343668c36373bde Mon Sep 17 00:00:00 2001
From: Eliot Horowitz <eliot@10gen.com>
Date: Fri, 15 Jan 2010 01:27:01 -0500
Subject: [PATCH] when scanning serially, if a chunk had no results, stopped
 prematurely SHARDING-71

---
 client/parallel.cpp        | 10 ++++++++--
 client/parallel.h          |  8 ++++++++
 jstests/sharding/shard2.js | 11 ++++++++++-
 s/cursors.cpp              |  3 ++-
 s/strategy_shard.cpp       |  4 +++-
 5 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/client/parallel.cpp b/client/parallel.cpp
index 418f99a7820..449f436550e 100644
--- a/client/parallel.cpp
+++ b/client/parallel.cpp
@@ -98,12 +98,18 @@ namespace mongo {
         if ( _current.get() && _current->more() )
             return true;
         
-        if ( _serverIndex >= _servers.size() )
+        if ( _serverIndex >= _servers.size() ){
             return false;
+        }
         
         ServerAndQuery& sq = _servers[_serverIndex++];
+
         _current = query( sq._server , 0 , sq._extra );
-        return _current->more();
+        if ( _current->more() )
+            return true;
+        
+        // this sq has nothing, so keep looking
+        return more();
     }
     
     BSONObj SerialServerClusteredCursor::next(){
diff --git a/client/parallel.h b/client/parallel.h
index 46660d4264c..5a22624e640 100644
--- a/client/parallel.h
+++ b/client/parallel.h
@@ -40,6 +40,8 @@ namespace mongo {
         
         static BSONObj concatQuery( const BSONObj& query , const BSONObj& extraFilter );
         
+        virtual string type() const = 0;
+
     protected:
         auto_ptr<DBClientCursor> query( const string& server , int num = 0 , BSONObj extraFilter = BSONObj() );
 
@@ -80,6 +82,10 @@ namespace mongo {
             return ss.str();
         }
 
+        operator string() const {
+            return toString();
+        }
+
         string _server;
         BSONObj _extra;
         BSONObj _orderObject;
@@ -95,6 +101,7 @@ namespace mongo {
         SerialServerClusteredCursor( set<ServerAndQuery> servers , QueryMessage& q , int sortOrder=0);
         virtual bool more();
         virtual BSONObj next();
+        virtual string type() const { return "SerialServer"; }
     private:
         vector<ServerAndQuery> _servers;
         unsigned _serverIndex;
@@ -115,6 +122,7 @@ namespace mongo {
         virtual ~ParallelSortClusteredCursor();
         virtual bool more();
         virtual BSONObj next();
+        virtual string type() const { return "ParallelSort"; }
     private:
         void _init();
         
diff --git a/jstests/sharding/shard2.js b/jstests/sharding/shard2.js
index 3a32d226ffd..566a0dbcc74 100644
--- a/jstests/sharding/shard2.js
+++ b/jstests/sharding/shard2.js
@@ -8,7 +8,7 @@ placeCheck = function( num ){
     print("shard2 step: " + num );
 }
 
-s = new ShardingTest( "shard2" , 2 , 5 );
+s = new ShardingTest( "shard2" , 2 , 6 );
 
 db = s.getDB( "test" );
 
@@ -142,6 +142,15 @@ function countCursor( c ){
 assert.eq( 6 , countCursor( db.foo.find()._exec() ) , "getMore 2" );
 assert.eq( 6 , countCursor( db.foo.find().limit(1)._exec() ) , "getMore 3" );
 
+// find by non-shard-key
+db.foo.find().forEach(
+    function(z){
+        var y = db.foo.findOne( { _id : z._id } );
+        assert( y , "_id check 1 : " + tojson( z ) );
+        assert.eq( z.num , y.num , "_id check 2 : " + tojson( z ) );
+    }
+);
+
 // update
 person = db.foo.findOne( { num : 3 } );
 assert.eq( "bob" , person.name , "update setup 1" );
diff --git a/s/cursors.cpp b/s/cursors.cpp
index 3354b96b8e4..23b8eaf695a 100644
--- a/s/cursors.cpp
+++ b/s/cursors.cpp
@@ -50,8 +50,9 @@ namespace mongo {
             b.append( (void*)o.objdata() , o.objsize() );
             num++;
             
-            if ( b.len() > maxSize )
+            if ( b.len() > maxSize ){
                 break;
+            }
 
             if ( num == ntoreturn ){
                 // soft limit aka batch size
diff --git a/s/strategy_shard.cpp b/s/strategy_shard.cpp
index dd52d6f8304..e38eeb84f9e 100644
--- a/s/strategy_shard.cpp
+++ b/s/strategy_shard.cpp
@@ -37,7 +37,7 @@ namespace mongo {
                 num++;
             }
             
-            if ( logLevel > 3 ){
+            if ( logLevel > 4 ){
                 StringBuilder ss;
                 ss << " shard query servers: " << servers.size() << "\n";
                 for ( set<ServerAndQuery>::iterator i = servers.begin(); i!=servers.end(); i++ ){
@@ -74,6 +74,8 @@ namespace mongo {
 
             assert( cursor );
             
+            log(5) << "   cursor type: " << cursor->type() << endl;
+
             ShardedClientCursor * cc = new ShardedClientCursor( q , cursor );
             if ( ! cc->sendNextBatch( r ) ){
                 delete( cursor );