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.cassandra.metrics;
  
  import javax.annotation.Nullable;
  
  import com.codahale.metrics.Histogram;
  import com.codahale.metrics.Meter;
  
  import static org.apache.cassandra.metrics.CassandraMetricsRegistry.Metrics;
  
  public class AccordClientRequestMetrics extends ClientRequestMetrics
  {
      public final @Nullable ClientRequestMetrics shared;
  
      public final Histogram keySize;
  
      // During migration back to Paxos it's possible a transaction runs
      // in an Epoch where Accord is no longer accepting transactions
      // and we still run it to completion, but we do skip the read from Cassandra
      // although it would be harmless. This should only occur briefly when coordinators
      // start transactions on the wrong protocol due to temporarily out of data cluster metadata.
      public final Meter migrationSkippedReads;
  
      // Number of times a key had to be run through PaxosRepair for migration to Accord
      public final Meter paxosKeyMigrations;
  
      // Number of times a query was rejected by Accord in TxnQuery due to a migration back to Paxos
      public final Meter accordMigrationRejects;
      public final Meter preempted;
      public final Meter topologyMismatches;
      public final boolean isWrite;
  
      public AccordClientRequestMetrics(String scope, ClientRequestMetrics shared, boolean isWrite)
      {
          super(scope);
          this.shared = shared;
          this.isWrite = isWrite;
  
          keySize = Metrics.histogram(factory.createMetricName("KeySizeHistogram"), false);
          migrationSkippedReads = Metrics.meter(factory.createMetricName("MigrationSkippedReads"));
          paxosKeyMigrations = Metrics.meter(factory.createMetricName("PaxosKeyMigrations"));
          accordMigrationRejects = Metrics.meter(factory.createMetricName("AccordMigrationRejects"));
          preempted = Metrics.meter(factory.createMetricName("Preempted"));
          topologyMismatches = Metrics.meter(factory.createMetricName("TopologyMismatches"));
      }
  
      @Override
      public void release()
      {
          super.release();
          Metrics.remove(factory.createMetricName("KeySizeHistogram"));
          Metrics.remove(factory.createMetricName("MigrationSkippedReads"));
          Metrics.remove(factory.createMetricName("PaxosKeyMigrations"));
          Metrics.remove(factory.createMetricName("AccordMigrationRejects"));
          Metrics.remove(factory.createMetricName("Preempted"));
          Metrics.remove(factory.createMetricName("TopologyMismatches"));
      }
  }
  