Promote C++ batch query execution functions to DBClientBase.

There's no good reason I can think of why the batch-processing forms of query()
shouldn't be available to all implementations of DBClientBase, and simply
optimized for DBClientConnection when exhaust-mode is available on the
connection.

This change facilitates another optimization, coming soon, which is that
DBDirectClient's batch query form can scan all rows rather than issuing a find
query when the query parameters are appropriate.  This allows for a clever
resolution of SERVER-4726, which is really about an unwanted log message.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/mongo/db/instance.h b/src/mongo/db/instance.h
index e57eccd1b5b..cf9698a95da 100644
--- a/src/mongo/db/instance.h
+++ b/src/mongo/db/instance.h
@@ -85,6 +85,8 @@ namespace mongo {
      */
     class DBDirectClient : public DBClientBase {
     public:
+        using DBClientBase::query;
+
         virtual auto_ptr<DBClientCursor> query(const string &ns, Query query, int nToReturn = 0, int nToSkip = 0,
                                                const BSONObj *fieldsToReturn = 0, int queryOptions = 0, int batchSize = 0);
 
@@ -117,6 +119,9 @@ namespace mongo {
         double getSoTimeout() const { return 0; }
 
         virtual bool lazySupported() const { return true; }
+
+        virtual QueryOptions _lookupAvailableOptions();
+
     private:
         static HostAndPort _clientHost;
     };