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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  package org.apache.hadoop.hbase.metrics;
19  
20  import org.apache.commons.logging.Log;
21  import org.apache.commons.logging.LogFactory;
22  import org.apache.hadoop.classification.InterfaceAudience;
23  import org.apache.hadoop.metrics.MetricsRecord;
24  import org.apache.hadoop.metrics.util.MetricsRegistry;
25  import org.apache.hadoop.metrics.util.MetricsTimeVaryingRate;
26  import org.apache.hadoop.util.StringUtils;
27  
28  /**
29   * This class extends MetricsTimeVaryingRate to let the metrics
30   * persist past a pushMetric() call
31   */
32  @Deprecated
33  @InterfaceAudience.Private
34  public class PersistentMetricsTimeVaryingRate extends MetricsTimeVaryingRate {
35    protected static final Log LOG =
36      LogFactory.getLog("org.apache.hadoop.hbase.metrics");
37  
38    protected boolean reset = false;
39    protected long lastOper = 0;
40    protected long totalOps = 0;
41  
42    /**
43     * Constructor - create a new metric
44     * @param nam the name of the metrics to be used to publish the metric
45     * @param registry - where the metrics object will be registered
46     * @param description metrics description
47     */
48    public PersistentMetricsTimeVaryingRate(final String nam, 
49        final MetricsRegistry registry, 
50        final String description) {
51      super(nam, registry, description);
52    }
53  
54    /**
55     * Constructor - create a new metric
56     * @param nam the name of the metrics to be used to publish the metric
57     * @param registry - where the metrics object will be registered
58     */
59    public PersistentMetricsTimeVaryingRate(final String nam, 
60        MetricsRegistry registry) {
61      this(nam, registry, NO_DESCRIPTION);
62    }
63  
64    /**
65     * Push updated metrics to the mr.
66     * 
67     * Note this does NOT push to JMX
68     * (JMX gets the info via {@link #getPreviousIntervalAverageTime()} and
69     * {@link #getPreviousIntervalNumOps()}
70     *
71     * @param mr owner of this metric
72     */
73    @Override
74    public synchronized void pushMetric(final MetricsRecord mr) {
75      // this will reset the currentInterval & num_ops += prevInterval()
76      super.pushMetric(mr);
77      // since we're retaining prevInterval(), we don't want to do the incr
78      // instead, we want to set that value because we have absolute ops
79      try {
80        mr.setMetric(getName() + "_num_ops", totalOps);
81      } catch (Exception e) {
82        LOG.info("pushMetric failed for " + getName() + "\n" +
83            StringUtils.stringifyException(e));
84      }
85      if (reset) {
86        // use the previous avg as our starting min/max/avg
87        super.inc(getPreviousIntervalAverageTime());
88        reset = false;
89      } else {
90        // maintain the stats that pushMetric() cleared
91        maintainStats();
92      }
93    }
94    
95    /**
96     * Increment the metrics for numOps operations
97     * @param numOps - number of operations
98     * @param time - time for numOps operations
99     */
100   @Override
101   public synchronized void inc(final int numOps, final long time) {
102     super.inc(numOps, time);
103     totalOps += numOps;
104   }
105   
106   /**
107    * Increment the metrics for numOps operations
108    * @param time - time for numOps operations
109    */
110   @Override
111   public synchronized void inc(final long time) {
112     super.inc(time);
113     ++totalOps;
114   }
115   
116   /**
117    * Rollover to a new interval
118    * NOTE: does not reset numOps.  this is an absolute value
119    */
120   public synchronized void resetMinMaxAvg() {
121     reset = true;
122   }
123 
124   /* MetricsTimeVaryingRate will reset every time pushMetric() is called
125    * This is annoying for long-running stats that might not get a single 
126    * operation in the polling period.  This function ensures that values
127    * for those stat entries don't get reset.
128    */
129   protected void maintainStats() {
130     int curOps = this.getPreviousIntervalNumOps();
131     if (curOps > 0) {
132       long curTime = this.getPreviousIntervalAverageTime();
133       long totalTime = curTime * curOps;
134       if (curTime == 0 || totalTime / curTime == curOps) {
135         super.inc(curOps, totalTime);
136       } else {
137         LOG.info("Stats for " + this.getName() + " overflowed! resetting");
138       }
139     }
140   }
141 }