diff --git a/sql/protocol.cc b/sql/protocol.cc
index b7be3f71d8e..8b652fe855a 100644
--- a/sql/protocol.cc
+++ b/sql/protocol.cc
@@ -857,8 +857,8 @@ bool Protocol_text::store(const char *from, size_t length,
 {
   CHARSET_INFO *tocs= this->thd->variables.character_set_results;
 #ifndef DBUG_OFF
-  DBUG_PRINT("info", ("Protocol_text::store field %u (%u): %s", field_pos,
-                      field_count, (length == 0? "" : from)));
+  DBUG_PRINT("info", ("Protocol_text::store field %u (%u): %.*s", field_pos,
+                      field_count, (int) length, (length == 0 ? "" : from)));
   DBUG_ASSERT(field_pos < field_count);
   DBUG_ASSERT(field_types == 0 ||
 	      field_types[field_pos] == MYSQL_TYPE_DECIMAL ||