diff --git a/storage/sphinx/ha_sphinx.cc b/storage/sphinx/ha_sphinx.cc
index 86332a741c6..d720f016408 100644
--- a/storage/sphinx/ha_sphinx.cc
+++ b/storage/sphinx/ha_sphinx.cc
@@ -2317,7 +2317,7 @@ int ha_sphinx::extra ( enum ha_extra_function op )
 }
 
 
-int ha_sphinx::write_row ( byte * )
+int ha_sphinx::write_row ( const byte * )
 {
 	SPH_ENTER_METHOD();
 	if ( !m_pShare || !m_pShare->m_bSphinxQL )
diff --git a/storage/sphinx/ha_sphinx.h b/storage/sphinx/ha_sphinx.h
index 8e6af908aab..decd88bad5a 100644
--- a/storage/sphinx/ha_sphinx.h
+++ b/storage/sphinx/ha_sphinx.h
@@ -85,7 +85,7 @@ public:
 	int				open ( const char * name, int mode, uint test_if_locked );
 	int				close ();
 
-	int				write_row ( byte * buf );
+	int				write_row ( const byte * buf );
 	int				update_row ( const byte * old_data, const byte * new_data );
 	int				delete_row ( const byte * buf );
 	int				extra ( enum ha_extra_function op );