content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.    
   */
  
  package org.apache.bifromq.basekv.store.range;
  
  import com.google.protobuf.ByteString;
  import java.util.Map;
  
  public interface IKVLoadTracker {
      interface ILoadRecorder {
          long startNanos();
  
          /**
           * Get the kv io times
           *
           * @return the access times to kv engine
           */
          int getKVIOs();
  
          /**
           * Get the total time spent on io of kv engine
           *
           * @return the total time in nanos
           */
          long getKVIONanos();
  
          Map<ByteString, Long> keyDistribution();
  
          /**
           * The latency spent for accessing this key
           *
           * @param key          the accessed key
           * @param latencyNanos the nanos spent
           */
          void record(ByteString key, long latencyNanos);
  
          /**
           * The latency spent for other kv activity
           *
           * @param latencyNanos the nanos spent
           */
          void record(long latencyNanos);
  
          void stop();
      }
  
      /**
       * Start a recorder
       *
       * @return the recorder
       */
      ILoadRecorder start();
  }
  