View Javadoc

1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.hadoop.hbase.client.metrics;
20  
21  import com.google.common.collect.ImmutableMap;
22  import org.apache.commons.logging.Log;
23  import org.apache.commons.logging.LogFactory;
24  import org.apache.hadoop.classification.InterfaceAudience;
25  import org.apache.hadoop.classification.InterfaceStability;
26  
27  import java.util.HashMap;
28  import java.util.Map;
29  import java.util.concurrent.atomic.AtomicLong;
30  
31  
32  /**
33   * Provides client-side metrics related to scan operations
34   * The data can be passed to mapreduce framework or other systems.
35   * We use atomic longs so that one thread can increment,
36   * while another atomically resets to zero after the values are reported
37   * to hadoop's counters.
38   *
39   * Some of these metrics are general for any client operation such as put
40   * However, there is no need for this. So they are defined under scan operation
41   * for now.
42   */
43  @InterfaceAudience.Public
44  @InterfaceStability.Evolving
45  public class ScanMetrics {
46  
47  
48    private static final Log LOG = LogFactory.getLog(ScanMetrics.class);
49  
50    /**
51     * Hash to hold the String -> Atomic Long mappings.
52     */
53    private final Map<String, AtomicLong> counters = new HashMap<String, AtomicLong>();
54  
55    // AtomicLongs to hold the metrics values.  These are all updated through ClientScanner and
56    // ScannerCallable.  They are atomic longs so that atomic getAndSet can be used to reset the
57    // values after progress is passed to hadoop's counters.
58  
59  
60    /**
61     * number of RPC calls
62     */
63    public final AtomicLong countOfRPCcalls = createCounter("RPC_CALLS");
64  
65    /**
66     * number of remote RPC calls
67     */
68    public final AtomicLong countOfRemoteRPCcalls = createCounter("REMOTE_RPC_CALLS");
69  
70    /**
71     * sum of milliseconds between sequential next calls
72     */
73    public final AtomicLong sumOfMillisSecBetweenNexts = createCounter("MILLIS_BETWEEN_NEXTS");
74  
75    /**
76     * number of NotServingRegionException caught
77     */
78    public final AtomicLong countOfNSRE = createCounter("NOT_SERVING_REGION_EXCEPTION");
79  
80    /**
81     * number of bytes in Result objects from region servers
82     */
83    public final AtomicLong countOfBytesInResults = createCounter("BYTES_IN_RESULTS");
84  
85    /**
86     * number of bytes in Result objects from remote region servers
87     */
88    public final AtomicLong countOfBytesInRemoteResults = createCounter("BYTES_IN_REMOTE_RESULTS");
89  
90    /**
91     * number of regions
92     */
93    public final AtomicLong countOfRegions = createCounter("REGIONS_SCANNED");
94  
95    /**
96     * number of RPC retries
97     */
98    public final AtomicLong countOfRPCRetries = createCounter("RPC_RETRIES");
99  
100   /**
101    * number of remote RPC retries
102    */
103   public final AtomicLong countOfRemoteRPCRetries = createCounter("REMOTE_RPC_RETRIES");
104 
105   /**
106    * constructor
107    */
108   public ScanMetrics() {
109   }
110 
111   private AtomicLong createCounter(String counterName) {
112     AtomicLong c = new AtomicLong(0);
113     counters.put(counterName, c);
114     return c;
115   }
116 
117   public void setCounter(String counterName, long value) {
118     AtomicLong c = this.counters.get(counterName);
119     if (c != null) {
120       c.set(value);
121     }
122   }
123 
124   /**
125    * Get all of the values since the last time this function was called.
126    *
127    * Calling this function will reset all AtomicLongs in the instance back to 0.
128    *
129    * @return A Map of String -> Long for metrics
130    */
131   public Map<String, Long> getMetricsMap() {
132     //Create a builder
133     ImmutableMap.Builder<String, Long> builder = ImmutableMap.builder();
134     //For every entry add the value and reset the AtomicLong back to zero
135     for (Map.Entry<String, AtomicLong> e : this.counters.entrySet()) {
136       builder.put(e.getKey(), e.getValue().getAndSet(0));
137     }
138     //Build the immutable map so that people can't mess around with it.
139     return builder.build();
140   }
141 
142 }