diff --git a/core/src/server/delivery/request/SearchCombineRequest.cpp b/core/src/server/delivery/request/SearchCombineRequest.cpp
index 1bf059f4ca..f5cccf7761 100644
--- a/core/src/server/delivery/request/SearchCombineRequest.cpp
+++ b/core/src/server/delivery/request/SearchCombineRequest.cpp
@@ -151,6 +151,15 @@ SearchCombineRequest::CanCombine(const SearchRequestPtr& request) {
         return false;
     }
 
+    // sum of nq must less-equal than MAX_NQ
+    if (vectors_data_.vector_count_ > MAX_NQ || request->VectorsData().vector_count_ > MAX_NQ) {
+        return false;
+    }
+    uint64_t total_nq = vectors_data_.vector_count_ + request->VectorsData().vector_count_;
+    if (total_nq > MAX_NQ) {
+        return false;
+    }
+
     // partition list must be equal for each one
     std::set<std::string> partition_list;
     GetUniqueList(request->PartitionList(), partition_list);
diff --git a/core/src/server/delivery/request/SearchRequest.h b/core/src/server/delivery/request/SearchRequest.h
index bdf08b745f..13cea49b2a 100644
--- a/core/src/server/delivery/request/SearchRequest.h
+++ b/core/src/server/delivery/request/SearchRequest.h
@@ -82,7 +82,7 @@ class SearchRequest : public BaseRequest {
 
  private:
     const std::string collection_name_;
-    const engine::VectorsData& vectors_data_;
+    const engine::VectorsData vectors_data_;
     int64_t topk_;
     milvus::json extra_params_;
     const std::vector<std::string> partition_list_;
diff --git a/core/src/utils/ValidationUtil.cpp b/core/src/utils/ValidationUtil.cpp
index 35a938069f..cd017cd997 100644
--- a/core/src/utils/ValidationUtil.cpp
+++ b/core/src/utils/ValidationUtil.cpp
@@ -325,12 +325,12 @@ ValidationUtil::ValidateSearchParams(const milvus::json& search_params,
 Status
 ValidationUtil::ValidateVectorData(const engine::VectorsData& vectors,
                                    const engine::meta::CollectionSchema& table_schema) {
-    if (vectors.float_data_.empty() && vectors.binary_data_.empty()) {
+    uint64_t vector_count = vectors.vector_count_;
+    if ((vectors.float_data_.empty() && vectors.binary_data_.empty()) || vector_count == 0) {
         return Status(SERVER_INVALID_ROWRECORD_ARRAY,
                       "The vector array is empty. Make sure you have entered vector records.");
     }
 
-    uint64_t vector_count = vectors.vector_count_;
     if (engine::utils::IsBinaryMetricType(table_schema.metric_type_)) {
         // check prepared binary data
         if (vectors.binary_data_.size() % vector_count != 0) {