text: // Copyright (C) 2019-2020 Zilliz. All rights reserved.
  //
  // Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
  // with the License. You may obtain a copy of the License at
  //
  // http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software distributed under the License
  // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
  // or implied. See the License for the specific language governing permissions and limitations under the License.
  
  #include "server/delivery/request/PreloadCollectionRequest.h"
  #include "server/DBWrapper.h"
  #include "server/ValidationUtil.h"
  #include "utils/Log.h"
  #include "utils/TimeRecorder.h"
  
  #include <fiu-local.h>
  #include <memory>
  
  namespace milvus {
  namespace server {
  
  PreloadCollectionRequest::PreloadCollectionRequest(const std::shared_ptr<milvus::server::Context>& context,
                                                     const std::string& collection_name)
      : BaseRequest(context, BaseRequest::kPreloadCollection), collection_name_(collection_name) {
  }
  
  BaseRequestPtr
  PreloadCollectionRequest::Create(const std::shared_ptr<milvus::server::Context>& context,
                                   const std::string& collection_name) {
      return std::shared_ptr<BaseRequest>(new PreloadCollectionRequest(context, collection_name));
  }
  
  Status
  PreloadCollectionRequest::OnExecute() {
      try {
          std::string hdr = "PreloadCollectionRequest(collection=" + collection_name_ + ")";
          TimeRecorderAuto rc(hdr);
  
          // step 1: check arguments
          auto status = ValidateCollectionName(collection_name_);
          if (!status.ok()) {
              return status;
          }
  
          // only process root collection, ignore partition collection
          engine::meta::CollectionSchema collection_schema;
          collection_schema.collection_id_ = collection_name_;
          status = DBWrapper::DB()->DescribeCollection(collection_schema);
          if (!status.ok()) {
              if (status.code() == DB_NOT_FOUND) {
                  return Status(SERVER_COLLECTION_NOT_EXIST, CollectionNotExistMsg(collection_name_));
              } else {
                  return status;
              }
          } else {
              if (!collection_schema.owner_collection_.empty()) {
                  return Status(SERVER_INVALID_COLLECTION_NAME, CollectionNotExistMsg(collection_name_));
              }
          }
  
          // step 2: force load collection data into cache
          // load each segment and insert into cache even cache capacity is not enough
          status = DBWrapper::DB()->PreloadCollection(context_, collection_name_, true);
          fiu_do_on("PreloadCollectionRequest.OnExecute.preload_collection_fail",
                    status = Status(milvus::SERVER_UNEXPECTED_ERROR, ""));
          fiu_do_on("PreloadCollectionRequest.OnExecute.throw_std_exception", throw std::exception());
          if (!status.ok()) {
              return status;
          }
      } catch (std::exception& ex) {
          return Status(SERVER_UNEXPECTED_ERROR, ex.what());
      }
  
      return Status::OK();
  }
  
  }  // namespace server
  }  // namespace milvus
  