Optimize some low efficient code (#20529) (#21683)

Signed-off-by: NLi Liu <li.liu@zilliz.com>

internal/core/src/segcore/Reduce.cpp

@@ -76,23 +76,24 @@ ReduceHelper::FilterInvalidSearchResult(SearchResult* search_result) {
     AssertInfo(search_result->distances_.size() == nq * topK,
                "wrong distances size, size = " + std::to_string(search_result->distances_.size()) +
                    ", expected size = " + std::to_string(nq * topK));
-    std::vector<int64_t> real_topks(nq);
-    std::vector<float> distances;
-    std::vector<int64_t> seg_offsets;
-    for (auto i = 0; i < nq; i++) {
-        real_topks[i] = 0;
-        for (auto j = 0; j < topK; j++) {
-            auto offset = i * topK + j;
-            if (search_result->seg_offsets_[offset] != INVALID_SEG_OFFSET) {
+    std::vector<int64_t> real_topks(nq, 0);
+    uint32_t valid_index = 0;
+    auto& offsets = search_result->seg_offsets_;
+    auto& distances = search_result->distances_;
+    for (auto i = 0; i < nq; ++i) {
+        for (auto j = 0; j < topK; ++j) {
+            auto index = i * topK + j;
+            if (offsets[index] != INVALID_SEG_OFFSET) {
                 real_topks[i]++;
-                seg_offsets.push_back(search_result->seg_offsets_[offset]);
-                distances.push_back(search_result->distances_[offset]);
+                offsets[valid_index] = offsets[index];
+                distances[valid_index] = distances[index];
+                valid_index++;
             }
         }
     }
+    offsets.resize(valid_index);
+    distances.resize(valid_index);
 
-    search_result->distances_.swap(distances);
-    search_result->seg_offsets_.swap(seg_offsets);
     search_result->topk_per_nq_prefix_sum_.resize(nq + 1);
     std::partial_sum(real_topks.begin(), real_topks.end(), search_result->topk_per_nq_prefix_sum_.begin() + 1);
 }
@@ -101,15 +102,16 @@ void
 ReduceHelper::FillPrimaryKey() {
     std::vector<SearchResult*> valid_search_results;
     // get primary keys for duplicates removal
-    for (auto search_result : search_results_) {
+    uint32_t valid_index = 0;
+    for (auto& search_result : search_results_) {
         FilterInvalidSearchResult(search_result);
         if (search_result->get_total_result_count() > 0) {
             auto segment = static_cast<SegmentInterface*>(search_result->segment_);
             segment->FillPrimaryKeys(plan_, *search_result);
-            valid_search_results.emplace_back(search_result);
+            search_results_[valid_index++] = search_result;
         }
     }
-    search_results_.swap(valid_search_results);
+    search_results_.resize(valid_index);
     num_segments_ = search_results_.size();
 }
 
@@ -119,20 +121,27 @@ ReduceHelper::RefreshSearchResult() {
         std::vector<int64_t> real_topks(total_nq_, 0);
         auto search_result = search_results_[i];
         if (search_result->result_offsets_.size() != 0) {
-            std::vector<milvus::PkType> primary_keys;
-            std::vector<float> distances;
-            std::vector<int64_t> seg_offsets;
+            uint32_t size = 0;
+            for (int j = 0; j < total_nq_; j++) {
+                size += final_search_records_[i][j].size();
+            }
+            std::vector<milvus::PkType> primary_keys(size);
+            std::vector<float> distances(size);
+            std::vector<int64_t> seg_offsets(size);
+
+            uint32_t index = 0;
             for (int j = 0; j < total_nq_; j++) {
                 for (auto offset : final_search_records_[i][j]) {
-                    primary_keys.push_back(search_result->primary_keys_[offset]);
-                    distances.push_back(search_result->distances_[offset]);
-                    seg_offsets.push_back(search_result->seg_offsets_[offset]);
+                    primary_keys[index] = search_result->primary_keys_[offset];
+                    distances[index] = search_result->distances_[offset];
+                    seg_offsets[index] = search_result->seg_offsets_[offset];
+                    index++;
                     real_topks[j]++;
                 }
             }
-            search_result->primary_keys_ = std::move(primary_keys);
-            search_result->distances_ = std::move(distances);
-            search_result->seg_offsets_ = std::move(seg_offsets);
+            search_result->primary_keys_.swap(primary_keys);
+            search_result->distances_.swap(distances);
+            search_result->seg_offsets_.swap(seg_offsets);
         }
         std::partial_sum(real_topks.begin(), real_topks.end(), search_result->topk_per_nq_prefix_sum_.begin() + 1);
     }