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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.regionserver;
19  
20  import java.lang.reflect.Method;
21  import java.util.HashMap;
22  import java.util.Map;
23  
24  import org.apache.commons.logging.Log;
25  import org.apache.commons.logging.LogFactory;
26  import org.apache.hadoop.hbase.HConstants;
27  import org.apache.hadoop.hbase.NotServingRegionException;
28  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.CloseRegionRequest;
29  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.CompactRegionRequest;
30  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.FlushRegionRequest;
31  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.GetRegionInfoRequest;
32  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.GetStoreFileRequest;
33  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.SplitRegionRequest;
34  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.GetRequest;
35  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MultiRequest;
36  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutateRequest;
37  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ScanRequest;
38  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.RegionSpecifier;
39  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.RequestHeader;
40  import org.apache.hadoop.hbase.regionserver.HRegionServer.QosPriority;
41  import org.apache.hadoop.hbase.util.Pair;
42  
43  import com.google.common.annotations.VisibleForTesting;
44  import com.google.common.base.Function;
45  import com.google.protobuf.Message;
46  import com.google.protobuf.TextFormat;
47  
48  
49  /**
50   * A guava function that will return a priority for use by QoS facility in regionserver; e.g.
51   * rpcs to hbase:meta and -ROOT-, etc., get priority.
52   */
53  // TODO: Remove.  This is doing way too much work just to figure a priority.  Do as Elliott
54  // suggests and just have the client specify a priority.
55  
56  //The logic for figuring out high priority RPCs is as follows:
57  //1. if the method is annotated with a QosPriority of QOS_HIGH,
58  //   that is honored
59  //2. parse out the protobuf message and see if the request is for meta
60  //   region, and if so, treat it as a high priority RPC
61  //Some optimizations for (2) are done here -
62  //Clients send the argument classname as part of making the RPC. The server
63  //decides whether to deserialize the proto argument message based on the
64  //pre-established set of argument classes (knownArgumentClasses below).
65  //This prevents the server from having to deserialize all proto argument
66  //messages prematurely.
67  //All the argument classes declare a 'getRegion' method that returns a
68  //RegionSpecifier object. Methods can be invoked on the returned object
69  //to figure out whether it is a meta region or not.
70  class QosFunction implements Function<Pair<RequestHeader, Message>, Integer> {
71    public static final Log LOG = LogFactory.getLog(QosFunction.class.getName());
72    private final Map<String, Integer> annotatedQos;
73    //We need to mock the regionserver instance for some unit tests (set via
74    //setRegionServer method.
75    private HRegionServer hRegionServer;
76    @SuppressWarnings("unchecked")
77    private final Class<? extends Message>[] knownArgumentClasses = new Class[]{
78        GetRegionInfoRequest.class,
79        GetStoreFileRequest.class,
80        CloseRegionRequest.class,
81        FlushRegionRequest.class,
82        SplitRegionRequest.class,
83        CompactRegionRequest.class,
84        GetRequest.class,
85        MutateRequest.class,
86        ScanRequest.class
87    };
88  
89    // Some caches for helping performance
90    private final Map<String, Class<? extends Message>> argumentToClassMap =
91      new HashMap<String, Class<? extends Message>>();
92    private final Map<String, Map<Class<? extends Message>, Method>> methodMap =
93      new HashMap<String, Map<Class<? extends Message>, Method>>();
94  
95    QosFunction(final HRegionServer hrs) {
96      this.hRegionServer = hrs;
97      Map<String, Integer> qosMap = new HashMap<String, Integer>();
98      for (Method m : HRegionServer.class.getMethods()) {
99        QosPriority p = m.getAnnotation(QosPriority.class);
100       if (p != null) {
101         // Since we protobuf'd, and then subsequently, when we went with pb style, method names
102         // are capitalized.  This meant that this brittle compare of method names gotten by
103         // reflection no longer matched the method names coming in over pb.  TODO: Get rid of this
104         // check.  For now, workaround is to capitalize the names we got from reflection so they
105         // have chance of matching the pb ones.
106         String capitalizedMethodName = capitalize(m.getName());
107         qosMap.put(capitalizedMethodName, p.priority());
108       }
109     }
110     this.annotatedQos = qosMap;
111 
112     if (methodMap.get("getRegion") == null) {
113       methodMap.put("hasRegion", new HashMap<Class<? extends Message>, Method>());
114       methodMap.put("getRegion", new HashMap<Class<? extends Message>, Method>());
115     }
116     for (Class<? extends Message> cls : knownArgumentClasses) {
117       argumentToClassMap.put(cls.getName(), cls);
118       try {
119         methodMap.get("hasRegion").put(cls, cls.getDeclaredMethod("hasRegion"));
120         methodMap.get("getRegion").put(cls, cls.getDeclaredMethod("getRegion"));
121       } catch (Exception e) {
122         throw new RuntimeException(e);
123       }
124     }
125   }
126 
127   private String capitalize(final String s) {
128     StringBuilder strBuilder = new StringBuilder(s);
129     strBuilder.setCharAt(0, Character.toUpperCase(strBuilder.charAt(0)));
130     return strBuilder.toString();
131   }
132 
133   public boolean isMetaRegion(byte[] regionName) {
134     HRegion region;
135     try {
136       region = hRegionServer.getRegion(regionName);
137     } catch (NotServingRegionException ignored) {
138       return false;
139     }
140     return region.getRegionInfo().isMetaTable();
141   }
142 
143   @Override
144   public Integer apply(Pair<RequestHeader, Message> headerAndParam) {
145     RequestHeader header = headerAndParam.getFirst();
146     String methodName = header.getMethodName();
147     Integer priorityByAnnotation = annotatedQos.get(methodName);
148     if (priorityByAnnotation != null) {
149       return priorityByAnnotation;
150     }
151 
152     Message param = headerAndParam.getSecond();
153     if (param == null) {
154       return HConstants.NORMAL_QOS;
155     }
156     if (methodName.equalsIgnoreCase("multi") && param instanceof MultiRequest) {
157       // The multi call has its priority set in the header.  All calls should work this way but
158       // only this one has been converted so far.  No priority == NORMAL_QOS.
159       return header.hasPriority()? header.getPriority(): HConstants.NORMAL_QOS;
160     }
161     String cls = param.getClass().getName();
162     Class<? extends Message> rpcArgClass = argumentToClassMap.get(cls);
163     RegionSpecifier regionSpecifier = null;
164     //check whether the request has reference to meta region or now.
165     try {
166       // Check if the param has a region specifier; the pb methods are hasRegion and getRegion if
167       // hasRegion returns true.  Not all listed methods have region specifier each time.  For
168       // example, the ScanRequest has it on setup but thereafter relies on the scannerid rather than
169       // send the region over every time.
170       Method hasRegion = methodMap.get("hasRegion").get(rpcArgClass);
171       if (hasRegion != null && (Boolean)hasRegion.invoke(param, (Object[])null)) {
172         Method getRegion = methodMap.get("getRegion").get(rpcArgClass);
173         regionSpecifier = (RegionSpecifier)getRegion.invoke(param, (Object[])null);
174         HRegion region = hRegionServer.getRegion(regionSpecifier);
175         if (region.getRegionInfo().isMetaTable()) {
176           if (LOG.isTraceEnabled()) {
177             LOG.trace("High priority because region=" + region.getRegionNameAsString());
178           }
179           return HConstants.HIGH_QOS;
180         }
181       }
182     } catch (Exception ex) {
183       // Not good throwing an exception out of here, a runtime anyways.  Let the query go into the
184       // server and have it throw the exception if still an issue.  Just mark it normal priority.
185       if (LOG.isTraceEnabled()) LOG.trace("Marking normal priority after getting exception=" + ex);
186       return HConstants.NORMAL_QOS;
187     }
188 
189     if (methodName.equals("scan")) { // scanner methods...
190       ScanRequest request = (ScanRequest)param;
191       if (!request.hasScannerId()) {
192         return HConstants.NORMAL_QOS;
193       }
194       RegionScanner scanner = hRegionServer.getScanner(request.getScannerId());
195       if (scanner != null && scanner.getRegionInfo().isMetaRegion()) {
196         if (LOG.isTraceEnabled()) {
197           // Scanner requests are small in size so TextFormat version should not overwhelm log.
198           LOG.trace("High priority scanner request " + TextFormat.shortDebugString(request));
199         }
200         return HConstants.HIGH_QOS;
201       }
202     }
203     return HConstants.NORMAL_QOS;
204   }
205 
206   @VisibleForTesting
207   void setRegionServer(final HRegionServer hrs) {
208     this.hRegionServer = hrs;
209   }
210 }