1 files changed, 4 insertions, 0 deletions
diff --git a/client/parallel.cpp b/client/parallel.cpp
index 412d4069b96..47b66a029cd 100644
--- a/client/parallel.cpp
+++ b/client/parallel.cpp
@@ -152,6 +152,10 @@ namespace mongo {
     }
 
     BSONObj ClusteredCursor::explain(){
+        // Note: by default we filter out allPlans and oldPlan in the shell's
+        // explain() function. If you add any recursive structures, make sure to
+        // edit the JS to make sure everything gets filtered.
+
         BSONObjBuilder b;
         b.append( "clusteredType" , type() );