From f0d9a01bccdaeb466c12c92057914bbfef59526c Mon Sep 17 00:00:00 2001
From: Antonin Kral <a.kral@bobek.cz>
Date: Thu, 15 Dec 2011 09:35:47 +0100
Subject: Imported Upstream version 2.0.2

---
 client/dbclient_rs.cpp | 66 +++++++++++++++++++++++++++++---------------------
 1 file changed, 39 insertions(+), 27 deletions(-)

(limited to 'client/dbclient_rs.cpp')

diff --git a/client/dbclient_rs.cpp b/client/dbclient_rs.cpp
index 2cab1f7..c57a52d 100644
--- a/client/dbclient_rs.cpp
+++ b/client/dbclient_rs.cpp
@@ -247,38 +247,27 @@ namespace mongo {
     }
 
     HostAndPort ReplicaSetMonitor::getSlave() {
+        LOG(2) << "dbclient_rs getSlave " << getServerAddress() << endl;
 
-        LOG(2) << "selecting new slave from replica set " << getServerAddress() << endl;
-
-        // Logic is to retry three times for any secondary node, if we can't find any secondary, we'll take
-        // any "ok" node
-        // TODO: Could this query hidden nodes?
-        const int MAX = 3;
-        for ( int xxx=0; xxx<MAX; xxx++ ) {
+        scoped_lock lk( _lock );
 
-            {
-                scoped_lock lk( _lock );
-                
-                unsigned i = 0;
-                for ( ; i<_nodes.size(); i++ ) {
-                    _nextSlave = ( _nextSlave + 1 ) % _nodes.size();
-                    if ( _nextSlave == _master ){
-                        LOG(2) << "not selecting " << _nodes[_nextSlave] << " as it is the current master" << endl;
-                        continue;
-                    }
-                    if ( _nodes[ _nextSlave ].okForSecondaryQueries() || ( _nodes[ _nextSlave ].ok && ( xxx + 1 ) >= MAX ) )
-                        return _nodes[ _nextSlave ].addr;
-                    
-                    LOG(2) << "not selecting " << _nodes[_nextSlave] << " as it is not ok to use" << endl;
-                }
-                
+        for ( unsigned ii = 0; ii < _nodes.size(); ii++ ) {
+            _nextSlave = ( _nextSlave + 1 ) % _nodes.size();
+            if ( _nextSlave != _master ) {
+                if ( _nodes[ _nextSlave ].okForSecondaryQueries() )
+                    return _nodes[ _nextSlave ].addr;
+                LOG(2) << "dbclient_rs getSlave not selecting " << _nodes[_nextSlave] << ", not currently okForSecondaryQueries" << endl;
             }
+        }
 
-            check(false);
+        if( _master >= 0 ) { 
+            assert( static_cast<unsigned>(_master) < _nodes.size() );
+            LOG(2) << "dbclient_rs getSlave no member in secondary state found, returning primary " << _nodes[ _master ] << endl;
+            return _nodes[_master].addr;
         }
         
-        LOG(2) << "no suitable slave nodes found, returning default node " << _nodes[ 0 ] << endl;
-
+        LOG(2) << "dbclient_rs getSlave no suitable member found, returning first node " << _nodes[ 0 ] << endl;
+        assert( _nodes.size() > 0 );
         return _nodes[0].addr;
     }
 
@@ -820,10 +809,14 @@ namespace mongo {
 
 
     bool DBClientReplicaSet::call( Message &toSend, Message &response, bool assertOk , string * actualServer ) {
+        const char * ns = 0;
+
         if ( toSend.operation() == dbQuery ) {
             // TODO: might be possible to do this faster by changing api
             DbMessage dm( toSend );
             QueryMessage qm( dm );
+            ns = qm.ns;
+
             if ( qm.queryOptions & QueryOption_SlaveOk ) {
                 for ( int i=0; i<3; i++ ) {
                     try {
@@ -844,7 +837,26 @@ namespace mongo {
         DBClientConnection* m = checkMaster();
         if ( actualServer )
             *actualServer = m->getServerAddress();
-        return m->call( toSend , response , assertOk );
+        
+        if ( ! m->call( toSend , response , assertOk ) )
+            return false;
+
+        if ( ns ) {
+            QueryResult * res = (QueryResult*)response.singleData();
+            if ( res->nReturned == 1 ) {
+                BSONObj x(res->data() );
+                if ( str::contains( ns , "$cmd" ) ) {
+                    if ( isNotMasterErrorString( x["errmsg"] ) )
+                        isntMaster();
+                }
+                else {
+                    if ( isNotMasterErrorString( getErrField( x ) ) )
+                        isntMaster();
+                }
+            }
+        }
+
+        return true;
     }
 
 }
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