SERVER-19569 AsyncResultsMerger ability to merge existing cursors

1 files changed, 11 insertions, 4 deletions

diff --git a/src/mongo/s/query/async_results_merger.h b/src/mongo/s/query/async_results_merger.h
index 1070e40e0a8..ba52c5ed08b 100644
--- a/src/mongo/s/query/async_results_merger.h
+++ b/src/mongo/s/query/async_results_merger.h
@@ -167,15 +167,22 @@ private:
         bool exhausted() const;
 
         HostAndPort hostAndPort;
-        BSONObj cmdObj;
+
+        // The command object for sending to the remote to establish the cursor. If a remote cursor
+        // has not been established yet, this member will be set to a valid command object. If a
+        // remote cursor has already been established, this member will be unset.
+        boost::optional<BSONObj> cmdObj;
+
+        // The cursor id for the remote cursor. If a remote cursor has not been established yet,
+        // this member will be unset. If a remote cursor has been established and is not yet
+        // exhausted, this member will be set to a valid non-zero cursor id. If a remote cursor was
+        // established but is now exhausted, this member will be set to zero.
         boost::optional<CursorId> cursorId;
+
         std::queue<BSONObj> docBuffer;
         executor::TaskExecutor::CallbackHandle cbHandle;
         Status status = Status::OK();
 
-        // Set to true once we have heard from the remote node at least once.
-        bool gotFirstResponse = false;
-
         // Count of fetched docs during ARM processing of the current batch. Used to reduce the
         // batchSize in getMore when mongod returned less docs than the requested batchSize.
         long long fetchedCount = 0;