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19 package org.apache.hadoop.hbase.regionserver;
20
21 import org.apache.commons.logging.Log;
22 import org.apache.commons.logging.LogFactory;
23 import org.apache.hadoop.conf.Configuration;
24 import org.apache.hadoop.hbase.HBaseInterfaceAudience;
25 import org.apache.hadoop.hbase.classification.InterfaceAudience;
26 import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
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39 @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
40 public class BusyRegionSplitPolicy extends IncreasingToUpperBoundRegionSplitPolicy {
41
42 private static final Log LOG = LogFactory.getLog(BusyRegionSplitPolicy.class);
43
44
45 private float maxBlockedRequests;
46 public static final float DEFAULT_MAX_BLOCKED_REQUESTS = 0.2f;
47
48
49 private long minAge = -1;
50 public static final long DEFAULT_MIN_AGE_MS = 600000;
51
52
53 private long aggregationWindow;
54 public static final long DEFAULT_AGGREGATION_WINDOW = 300000;
55
56 private HRegion region;
57 private long prevTime;
58 private long startTime;
59 private long writeRequestCount;
60 private long blockedRequestCount;
61 private float blockedRate;
62
63 @Override
64 protected void configureForRegion(final HRegion region) {
65 super.configureForRegion(region);
66 this.region = region;
67 Configuration conf = getConf();
68
69 maxBlockedRequests = conf.getFloat("hbase.busy.policy.blockedRequests",
70 DEFAULT_MAX_BLOCKED_REQUESTS);
71 minAge = conf.getLong("hbase.busy.policy.minAge", DEFAULT_MIN_AGE_MS);
72 aggregationWindow = conf.getLong("hbase.busy.policy.aggWindow",
73 DEFAULT_AGGREGATION_WINDOW);
74
75 if (maxBlockedRequests < 0.00001f || maxBlockedRequests > 0.99999f) {
76 LOG.warn("Threshold for maximum blocked requests is set too low or too high, "
77 + " resetting to default of " + DEFAULT_MAX_BLOCKED_REQUESTS);
78 maxBlockedRequests = DEFAULT_MAX_BLOCKED_REQUESTS;
79 }
80
81 if (aggregationWindow <= 0) {
82 LOG.warn("Aggregation window size is too low: " + aggregationWindow
83 + ". Resetting it to default of " + DEFAULT_AGGREGATION_WINDOW);
84 aggregationWindow = DEFAULT_AGGREGATION_WINDOW;
85 }
86
87 init();
88 }
89
90 private synchronized void init() {
91 startTime = EnvironmentEdgeManager.currentTime();
92 prevTime = startTime;
93 blockedRequestCount = region.getBlockedRequestsCount();
94 writeRequestCount = region.getWriteRequestsCount();
95 }
96
97 @Override
98 protected boolean shouldSplit() {
99 float blockedReqRate = updateRate();
100 if (super.shouldSplit()) {
101 return true;
102 }
103
104 if (EnvironmentEdgeManager.currentTime() < startTime + minAge) {
105 return false;
106 }
107
108 for (Store store: region.getStores()) {
109 if (!store.canSplit()) {
110 return false;
111 }
112 }
113
114 if (blockedReqRate >= maxBlockedRequests) {
115 if (LOG.isDebugEnabled()) {
116 LOG.debug("Going to split region " + region.getRegionInfo().getRegionNameAsString()
117 + " because it's too busy. Blocked Request rate: " + blockedReqRate);
118 }
119 return true;
120 }
121
122 return false;
123 }
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131
132 private synchronized float updateRate() {
133 float aggBlockedRate;
134 long curTime = EnvironmentEdgeManager.currentTime();
135
136 long newBlockedReqs = region.getBlockedRequestsCount();
137 long newWriteReqs = region.getWriteRequestsCount();
138
139 aggBlockedRate =
140 (newBlockedReqs - blockedRequestCount) / (newWriteReqs - writeRequestCount + 0.00001f);
141
142 if (curTime - prevTime >= aggregationWindow) {
143 blockedRate = aggBlockedRate;
144 prevTime = curTime;
145 blockedRequestCount = newBlockedReqs;
146 writeRequestCount = newWriteReqs;
147 } else if (curTime - startTime >= aggregationWindow) {
148
149
150 float timeSlice = (curTime - prevTime) / (aggregationWindow + 0.0f);
151 aggBlockedRate = (1 - timeSlice) * blockedRate + timeSlice * aggBlockedRate;
152 } else {
153 aggBlockedRate = 0.0f;
154 }
155 return aggBlockedRate;
156 }
157 }