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.index.sai.metrics;
  
  import java.util.concurrent.TimeUnit;
  
  import com.codahale.metrics.Counter;
  import com.codahale.metrics.Histogram;
  import com.codahale.metrics.Timer;
  import org.apache.cassandra.index.sai.QueryContext;
  import org.apache.cassandra.schema.TableMetadata;
  import org.apache.cassandra.tracing.Tracing;
  
  import static org.apache.cassandra.metrics.CassandraMetricsRegistry.Metrics;
  
  public class TableQueryMetrics extends AbstractMetrics
  {
      public static final String TABLE_QUERY_METRIC_TYPE = "TableQueryMetrics";
  
      public final Timer postFilteringReadLatency;
  
      private final PerQueryMetrics perQueryMetrics;
  
      private final Counter totalQueryTimeouts;
      private final Counter totalPartitionReads;
      private final Counter totalRowsFiltered;
      private final Counter totalQueriesCompleted;
  
      public TableQueryMetrics(TableMetadata table)
      {
          super(table.keyspace, table.name, TABLE_QUERY_METRIC_TYPE);
  
          perQueryMetrics = new PerQueryMetrics(table);
  
          postFilteringReadLatency = Metrics.timer(createMetricName("PostFilteringReadLatency"));
  
          totalPartitionReads = Metrics.counter(createMetricName("TotalPartitionReads"));
          totalRowsFiltered = Metrics.counter(createMetricName("TotalRowsFiltered"));
          totalQueriesCompleted = Metrics.counter(createMetricName("TotalQueriesCompleted"));
          totalQueryTimeouts = Metrics.counter(createMetricName("TotalQueryTimeouts"));
      }
  
      public void record(QueryContext queryContext)
      {
          if (queryContext.queryTimedOut)
              totalQueryTimeouts.inc();
  
          perQueryMetrics.record(queryContext);
      }
  
      public void release()
      {
          super.release();
          perQueryMetrics.release();
      }
  
      public class PerQueryMetrics extends AbstractMetrics
      {
          public static final String PER_QUERY_METRICS_TYPE = "PerQuery";
  
          private final Timer queryLatency;
  
          /**
           * Global metrics for all indices hit during the query.
           */
          private final Histogram sstablesHit;
          private final Histogram segmentsHit;
          private final Histogram partitionReads;
          private final Histogram rowsFiltered;
  
          /**
           * Balanced tree index metrics.
           */
          private final Histogram balancedTreePostingsNumPostings;
          /**
           * Balanced tree index posting lists metrics.
           */
          private final Histogram balancedTreePostingsSkips;
          private final Histogram balancedTreePostingsDecodes;
  
          /**
           * Trie index posting lists metrics.
           */
          private final Histogram postingsSkips;
          private final Histogram postingsDecodes;
  
          public PerQueryMetrics(TableMetadata table)
          {
              super(table.keyspace, table.name, PER_QUERY_METRICS_TYPE);
  
              queryLatency = Metrics.timer(createMetricName("QueryLatency"));
  
              sstablesHit = Metrics.histogram(createMetricName("SSTableIndexesHit"), false);
              segmentsHit = Metrics.histogram(createMetricName("IndexSegmentsHit"), false);
  
              balancedTreePostingsSkips = Metrics.histogram(createMetricName("BalancedTreePostingsSkips"), false);
  
              balancedTreePostingsNumPostings = Metrics.histogram(createMetricName("BalancedTreePostingsNumPostings"), false);
              balancedTreePostingsDecodes = Metrics.histogram(createMetricName("BalancedTreePostingsDecodes"), false);
  
              postingsSkips = Metrics.histogram(createMetricName("PostingsSkips"), false);
              postingsDecodes = Metrics.histogram(createMetricName("PostingsDecodes"), false);
  
              partitionReads = Metrics.histogram(createMetricName("PartitionReads"), false);
              rowsFiltered = Metrics.histogram(createMetricName("RowsFiltered"), false);
          }
  
          private void recordStringIndexCacheMetrics(QueryContext events)
          {
              postingsSkips.update(events.triePostingsSkips);
              postingsDecodes.update(events.triePostingsDecodes);
          }
  
          private void recordNumericIndexCacheMetrics(QueryContext events)
          {
              balancedTreePostingsNumPostings.update(events.balancedTreePostingListsHit);
  
              balancedTreePostingsSkips.update(events.balancedTreePostingsSkips);
              balancedTreePostingsDecodes.update(events.balancedTreePostingsDecodes);
          }
  
          public void record(QueryContext queryContext)
          {
              final long totalQueryTimeNs = queryContext.totalQueryTimeNs();
              queryLatency.update(totalQueryTimeNs, TimeUnit.NANOSECONDS);
              final long queryLatencyMicros = TimeUnit.NANOSECONDS.toMicros(totalQueryTimeNs);
  
              sstablesHit.update(queryContext.sstablesHit);
              segmentsHit.update(queryContext.segmentsHit);
  
              partitionReads.update(queryContext.partitionsRead);
              totalPartitionReads.inc(queryContext.partitionsRead);
  
              rowsFiltered.update(queryContext.rowsFiltered);
              totalRowsFiltered.inc(queryContext.rowsFiltered);
  
              if (Tracing.isTracing())
              {
                  Tracing.trace("Index query accessed memtable indexes, {}, and {}, post-filtered {} in {}, and took {} microseconds.",
                                pluralize(queryContext.sstablesHit, "SSTable index", "es"), pluralize(queryContext.segmentsHit, "segment", "s"),
                                pluralize(queryContext.rowsFiltered, "row", "s"), pluralize(queryContext.partitionsRead, "partition", "s"),
                                queryLatencyMicros);
              }
  
              if (queryContext.trieSegmentsHit > 0)
              {
                  recordStringIndexCacheMetrics(queryContext);
              }
  
              if (queryContext.balancedTreeSegmentsHit > 0)
              {
                  recordNumericIndexCacheMetrics(queryContext);
              }
  
              totalQueriesCompleted.inc();
          }
      }
  
      private String pluralize(long count, String root, String plural)
      {
          return count == 1 ? String.format("1 %s", root) : String.format("%d %s%s", count, root, plural);
      }
  }
  