Log query for opt error

src/graph/service/QueryInstance.cpp

@@ -93,7 +93,8 @@ Status QueryInstance::validateAndOptimize() {
   // Optimize the query, and get the execution plan. We should not pass the optimizer errors to user
   // since the message is often not easy to understand. Logging them is enough.
   if (auto status = findBestPlan(); !status.ok()) {
-    LOG(ERROR) << "Error found in optimization stage: " << status.message();
+    LOG(ERROR) << "Error found in optimization stage for query: " << rctx->query()
+               << ", error: " << status.message();
     return Status::Error(
         "There are some errors found in optimizer, "
         "please contact to the admin to learn more details");