fix too many data copies (#2784)

Signed-off-by: Nshengjun.li <shengjun.li@zilliz.com>

CHANGELOG.md

@@ -17,6 +17,7 @@ Please mark all change in change log and use the issue from GitHub
 -   \#2690 Remove body parser in show-partitions endpoints
 -   \#2692 Milvus hangs during multi-thread concurrent search
 -   \#2739 Fix mishards start failed
+-   \#2776 Fix too many data copies during creating IVF index
 
 ## Feature
 

core/src/index/knowhere/knowhere/index/vector_index/IndexIVF.cpp

@@ -66,13 +66,11 @@ void
 IVF::Train(const DatasetPtr& dataset_ptr, const Config& config) {
     GETTENSOR(dataset_ptr)
 
-    faiss::Index* coarse_quantizer = new faiss::IndexFlatL2(dim);
-    int64_t nlist = config[IndexParams::nlist].get<int64_t>();
     faiss::MetricType metric_type = GetMetricType(config[Metric::TYPE].get<std::string>());
-    auto index = std::make_shared<faiss::IndexIVFFlat>(coarse_quantizer, dim, nlist, metric_type);
-    index->train(rows, (float*)p_data);
-
-    index_.reset(faiss::clone_index(index.get()));
+    faiss::Index* coarse_quantizer = new faiss::IndexFlat(dim, metric_type);
+    int64_t nlist = config[IndexParams::nlist].get<int64_t>();
+    index_ = std::shared_ptr<faiss::Index>(new faiss::IndexIVFFlat(coarse_quantizer, dim, nlist, metric_type));
+    index_->train(rows, (float*)p_data);
 }
 
 void

core/src/index/knowhere/knowhere/index/vector_index/IndexIVFPQ.cpp

@@ -35,13 +35,13 @@ void
 IVFPQ::Train(const DatasetPtr& dataset_ptr, const Config& config) {
     GETTENSOR(dataset_ptr)
 
-    faiss::Index* coarse_quantizer = new faiss::IndexFlat(dim, GetMetricType(config[Metric::TYPE].get<std::string>()));
-    auto index = std::make_shared<faiss::IndexIVFPQ>(coarse_quantizer, dim, config[IndexParams::nlist].get<int64_t>(),
-                                                     config[IndexParams::m].get<int64_t>(),
-                                                     config[IndexParams::nbits].get<int64_t>());
-    index->train(rows, (float*)p_data);
+    faiss::MetricType metric_type = GetMetricType(config[Metric::TYPE].get<std::string>());
+    faiss::Index* coarse_quantizer = new faiss::IndexFlat(dim, metric_type);
+    index_ = std::shared_ptr<faiss::Index>(new faiss::IndexIVFPQ(
+        coarse_quantizer, dim, config[IndexParams::nlist].get<int64_t>(), config[IndexParams::m].get<int64_t>(),
+        config[IndexParams::nbits].get<int64_t>(), metric_type));
 
-    index_.reset(faiss::clone_index(index.get()));
+    index_->train(rows, (float*)p_data);
 }
 
 VecIndexPtr

core/src/index/knowhere/knowhere/index/vector_index/IndexIVFSQ.cpp

@@ -38,11 +38,9 @@ IVFSQ::Train(const DatasetPtr& dataset_ptr, const Config& config) {
     std::stringstream index_type;
     index_type << "IVF" << config[IndexParams::nlist] << ","
                << "SQ" << config[IndexParams::nbits];
-    auto build_index =
-        faiss::index_factory(dim, index_type.str().c_str(), GetMetricType(config[Metric::TYPE].get<std::string>()));
-    build_index->train(rows, (float*)p_data);
-
-    index_.reset(faiss::clone_index(build_index));
+    index_ = std::shared_ptr<faiss::Index>(
+        faiss::index_factory(dim, index_type.str().c_str(), GetMetricType(config[Metric::TYPE].get<std::string>())));
+    index_->train(rows, (float*)p_data);
 }
 
 VecIndexPtr

core/src/index/knowhere/knowhere/index/vector_index/IndexNSG.cpp

@@ -139,9 +139,7 @@ NSG::Train(const DatasetPtr& dataset_ptr, const Config& config) {
     b_params.out_degree = config[IndexParams::out_degree];
     b_params.search_length = config[IndexParams::search_length];
 
-    auto p_ids = dataset_ptr->Get<const int64_t*>(meta::IDS);
-
-    GETTENSOR(dataset_ptr)
+    GETTENSORWITHIDS(dataset_ptr)
     index_ = std::make_shared<impl::NsgIndex>(dim, rows, config[Metric::TYPE].get<std::string>());
     index_->SetKnnGraph(knng);
     index_->Build_with_ids(rows, (float*)p_data, (int64_t*)p_ids, b_params);