SERVER-17216 2.6 mongostat should not crash if connected to a 3.0 mongod, and warn if detected

Closes #922

Signed-off-by: Ramon Fernandez <ramon.fernandez@mongodb.com>

2 files changed, 16 insertions, 3 deletions

diff --git a/src/mongo/tools/stat.cpp b/src/mongo/tools/stat.cpp
index 30bb78252e1..002d8a4a5f0 100644
--- a/src/mongo/tools/stat.cpp
+++ b/src/mongo/tools/stat.cpp
@@ -151,6 +151,7 @@ namespace mongo {
                 return -1;
 
             int maxLockedDbWidth = 0;
+            bool warned = false;
 
             while (mongoStatGlobalParams.rowCount == 0 ||
                    rowNum < mongoStatGlobalParams.rowCount) {
@@ -169,6 +170,11 @@ namespace mongo {
 
                 try {
 
+                    if ( !warned && now["storageEngine"].type() ) {
+                       toolError() << "warning: detected a 3.0 mongod, some columns not applicable" << endl;
+                       warned = true;
+                    }
+
                     BSONObj out = _statUtil.doRow( prev , now );
 
                     // adjust width up as longer 'locked db' values appear
@@ -230,6 +236,7 @@ namespace mongo {
 
         static void serverThread( shared_ptr<ServerState> state , int sleepTime) {
             try {
+                bool warned = false;
                 DBClientConnection conn( true );
                 conn._logLevel = logger::LogSeverity::Debug(1);
                 string errmsg;
@@ -260,6 +267,10 @@ namespace mongo {
                             state->error = errorStream;
                             state->lastUpdate = time(0);
                         }
+                        if ( !warned && out["storageEngine"].type() ) {
+                           toolError() << "warning: detected a 3.0 mongod, some columns not applicable" << endl;
+                           warned = true;
+                        }
 
                         if ( out["shardCursorType"].type() == Object ||
                              out["process"].str() == "mongos" ) {
diff --git a/src/mongo/tools/stat_util.cpp b/src/mongo/tools/stat_util.cpp
index 7117d7ce511..d8d7c51e74b 100644
--- a/src/mongo/tools/stat_util.cpp
+++ b/src/mongo/tools/stat_util.cpp
@@ -331,9 +331,11 @@ namespace mongo {
             NamespaceInfo& s = stats[e.fieldName()];
             s.ns = e.fieldName();
             
-            BSONObj temp = e.Obj()["timeLockedMicros"].Obj();
-            s.read = ( temp["r"].numberLong() + temp["R"].numberLong() ) / 1000;
-            s.write = ( temp["w"].numberLong() + temp["W"].numberLong() ) / 1000;
+            if ( e.Obj()["timeLockedMicros"].isABSONObj() ){
+                BSONObj temp = e.Obj()["timeLockedMicros"].Obj();
+                s.read = ( temp["r"].numberLong() + temp["R"].numberLong() ) / 1000;
+                s.write = ( temp["w"].numberLong() + temp["W"].numberLong() ) / 1000;
+            }
         }
         
         return stats;