diff --git a/dbsim/db_client_service.hpp b/dbsim/db_client_service.hpp
index 1239f92..8b4cb53 100644
--- a/dbsim/db_client_service.hpp
+++ b/dbsim/db_client_service.hpp
@@ -33,6 +33,7 @@ namespace db
     public:
         client_service(db::client& client);
 
+        std::string query() const override { return ""; }
         bool interrupted(wsrep::unique_lock<wsrep::mutex>&)
             const override
         { return false; }
@@ -43,6 +44,10 @@ namespace db
             return 0;
         }
         void cleanup_transaction() override { }
+        bool is_xa () const override
+        {
+            return false;
+        }
         size_t bytes_generated() const override
         {
             return 0;
diff --git a/include/wsrep/client_service.hpp b/include/wsrep/client_service.hpp
index 7067b99..a4637e1 100644
--- a/include/wsrep/client_service.hpp
+++ b/include/wsrep/client_service.hpp
@@ -40,7 +40,7 @@ namespace wsrep
         client_service() { }
         virtual ~client_service() { }
 
-        virtual const char* query() const = 0;
+        virtual std::string query() const = 0;
 
         /**
          * Return true if the current transaction has been interrupted
diff --git a/test/mock_client_state.hpp b/test/mock_client_state.hpp
index 899ca68..ff070e1 100644
--- a/test/mock_client_state.hpp
+++ b/test/mock_client_state.hpp
@@ -76,6 +76,8 @@ namespace wsrep
             , aborts_()
         { }
 
+        std::string query() const WSREP_OVERRIDE { return ""; }
+
         int bf_rollback() WSREP_OVERRIDE;
 
         bool interrupted(wsrep::unique_lock<wsrep::mutex>&)
@@ -126,6 +128,12 @@ namespace wsrep
         }
 
         void cleanup_transaction() WSREP_OVERRIDE { }
+
+        bool is_xa() const WSREP_OVERRIDE
+        {
+            return false;
+        }
+
         size_t bytes_generated() const WSREP_OVERRIDE
         {
             return bytes_generated_;