001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.client.metrics;
019
020import java.util.HashMap;
021import java.util.Map;
022import java.util.concurrent.atomic.AtomicLong;
023import org.apache.yetus.audience.InterfaceAudience;
024
025import org.apache.hbase.thirdparty.com.google.common.collect.ImmutableMap;
026
027/**
028 * Provides server side metrics related to scan operations.
029 */
030@InterfaceAudience.Public
031@SuppressWarnings("checkstyle:VisibilityModifier") // See HBASE-27757
032public class ServerSideScanMetrics {
033  /**
034   * Hash to hold the String -> Atomic Long mappings for each metric
035   */
036  private final Map<String, AtomicLong> counters = new HashMap<>();
037
038  /**
039   * Create a new counter with the specified name
040   * @return {@link AtomicLong} instance for the counter with counterName
041   */
042  protected AtomicLong createCounter(String counterName) {
043    AtomicLong c = new AtomicLong(0);
044    counters.put(counterName, c);
045    return c;
046  }
047
048  public static final String COUNT_OF_ROWS_SCANNED_KEY_METRIC_NAME = "ROWS_SCANNED";
049  public static final String COUNT_OF_ROWS_FILTERED_KEY_METRIC_NAME = "ROWS_FILTERED";
050
051  public static final String BLOCK_BYTES_SCANNED_KEY_METRIC_NAME = "BLOCK_BYTES_SCANNED";
052
053  /**
054   * number of rows filtered during scan RPC
055   */
056  public final AtomicLong countOfRowsFiltered =
057    createCounter(COUNT_OF_ROWS_FILTERED_KEY_METRIC_NAME);
058
059  /**
060   * number of rows scanned during scan RPC. Not every row scanned will be returned to the client
061   * since rows may be filtered.
062   */
063  public final AtomicLong countOfRowsScanned = createCounter(COUNT_OF_ROWS_SCANNED_KEY_METRIC_NAME);
064
065  public final AtomicLong countOfBlockBytesScanned =
066    createCounter(BLOCK_BYTES_SCANNED_KEY_METRIC_NAME);
067
068  public void setCounter(String counterName, long value) {
069    AtomicLong c = this.counters.get(counterName);
070    if (c != null) {
071      c.set(value);
072    }
073  }
074
075  /** Returns true if a counter exists with the counterName */
076  public boolean hasCounter(String counterName) {
077    return this.counters.containsKey(counterName);
078  }
079
080  /** Returns {@link AtomicLong} instance for this counter name, null if counter does not exist. */
081  public AtomicLong getCounter(String counterName) {
082    return this.counters.get(counterName);
083  }
084
085  public void addToCounter(String counterName, long delta) {
086    AtomicLong c = this.counters.get(counterName);
087    if (c != null) {
088      c.addAndGet(delta);
089    }
090  }
091
092  /**
093   * Get all of the values since the last time this function was called. Calling this function will
094   * reset all AtomicLongs in the instance back to 0.
095   * @return A Map of String -&gt; Long for metrics
096   */
097  public Map<String, Long> getMetricsMap() {
098    return getMetricsMap(true);
099  }
100
101  /**
102   * Get all of the values. If reset is true, we will reset the all AtomicLongs back to 0.
103   * @param reset whether to reset the AtomicLongs to 0.
104   * @return A Map of String -&gt; Long for metrics
105   */
106  public Map<String, Long> getMetricsMap(boolean reset) {
107    // Create a builder
108    ImmutableMap.Builder<String, Long> builder = ImmutableMap.builder();
109    for (Map.Entry<String, AtomicLong> e : this.counters.entrySet()) {
110      long value = reset ? e.getValue().getAndSet(0) : e.getValue().get();
111      builder.put(e.getKey(), value);
112    }
113    // Build the immutable map so that people can't mess around with it.
114    return builder.build();
115  }
116}