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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.conf.Configuration;
27  import org.apache.hadoop.hbase.HConstants;
28  import org.apache.hadoop.hbase.classification.InterfaceAudience;
29  import org.apache.hadoop.hbase.ipc.PriorityFunction;
30  import org.apache.hadoop.hbase.ipc.QosPriority;
31  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.CloseRegionRequest;
32  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.CompactRegionRequest;
33  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.FlushRegionRequest;
34  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.GetRegionInfoRequest;
35  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.GetStoreFileRequest;
36  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.SplitRegionRequest;
37  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.GetRequest;
38  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MultiRequest;
39  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutateRequest;
40  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ScanRequest;
41  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.RegionSpecifier;
42  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.RequestHeader;
43  
44  import com.google.common.annotations.VisibleForTesting;
45  import com.google.protobuf.Message;
46  import com.google.protobuf.TextFormat;
47  import org.apache.hadoop.hbase.security.User;
48  
49  /**
50   * Reads special method annotations and table names to figure a priority for use by QoS facility in
51   * ipc; e.g: rpcs to hbase:meta 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  @InterfaceAudience.Private
71  public class AnnotationReadingPriorityFunction implements PriorityFunction {
72    private static final Log LOG =
73      LogFactory.getLog(AnnotationReadingPriorityFunction.class.getName());
74  
75    /** Used to control the scan delay, currently sqrt(numNextCall * weight) */
76    public static final String SCAN_VTIME_WEIGHT_CONF_KEY = "hbase.ipc.server.scan.vtime.weight";
77  
78    protected final Map<String, Integer> annotatedQos;
79    //We need to mock the regionserver instance for some unit tests (set via
80    //setRegionServer method.
81    private RSRpcServices rpcServices;
82    @SuppressWarnings("unchecked")
83    private final Class<? extends Message>[] knownArgumentClasses = new Class[]{
84        GetRegionInfoRequest.class,
85        GetStoreFileRequest.class,
86        CloseRegionRequest.class,
87        FlushRegionRequest.class,
88        SplitRegionRequest.class,
89        CompactRegionRequest.class,
90        GetRequest.class,
91        MutateRequest.class,
92        ScanRequest.class
93    };
94  
95    // Some caches for helping performance
96    private final Map<String, Class<? extends Message>> argumentToClassMap =
97      new HashMap<String, Class<? extends Message>>();
98    private final Map<String, Map<Class<? extends Message>, Method>> methodMap =
99      new HashMap<String, Map<Class<? extends Message>, Method>>();
100 
101   private final float scanVirtualTimeWeight;
102 
103   /**
104    * Calls {@link #AnnotationReadingPriorityFunction(RSRpcServices, Class)} using the result of
105    * {@code rpcServices#getClass()}
106    *
107    * @param rpcServices
108    *          The RPC server implementation
109    */
110   public AnnotationReadingPriorityFunction(final RSRpcServices rpcServices) {
111     this(rpcServices, rpcServices.getClass());
112   }
113 
114   /**
115    * Constructs the priority function given the RPC server implementation and the annotations on the
116    * methods in the provided {@code clz}.
117    *
118    * @param rpcServices
119    *          The RPC server implementation
120    * @param clz
121    *          The concrete RPC server implementation's class
122    */
123   public AnnotationReadingPriorityFunction(final RSRpcServices rpcServices,
124       Class<? extends RSRpcServices> clz) {
125     Map<String,Integer> qosMap = new HashMap<String,Integer>();
126     for (Method m : clz.getMethods()) {
127       QosPriority p = m.getAnnotation(QosPriority.class);
128       if (p != null) {
129         // Since we protobuf'd, and then subsequently, when we went with pb style, method names
130         // are capitalized.  This meant that this brittle compare of method names gotten by
131         // reflection no longer matched the method names coming in over pb.  TODO: Get rid of this
132         // check.  For now, workaround is to capitalize the names we got from reflection so they
133         // have chance of matching the pb ones.
134         String capitalizedMethodName = capitalize(m.getName());
135         qosMap.put(capitalizedMethodName, p.priority());
136       }
137     }
138     this.rpcServices = rpcServices;
139     this.annotatedQos = qosMap;
140     if (methodMap.get("getRegion") == null) {
141       methodMap.put("hasRegion", new HashMap<Class<? extends Message>, Method>());
142       methodMap.put("getRegion", new HashMap<Class<? extends Message>, Method>());
143     }
144     for (Class<? extends Message> cls : knownArgumentClasses) {
145       argumentToClassMap.put(cls.getName(), cls);
146       try {
147         methodMap.get("hasRegion").put(cls, cls.getDeclaredMethod("hasRegion"));
148         methodMap.get("getRegion").put(cls, cls.getDeclaredMethod("getRegion"));
149       } catch (Exception e) {
150         throw new RuntimeException(e);
151       }
152     }
153 
154     Configuration conf = rpcServices.getConfiguration();
155     scanVirtualTimeWeight = conf.getFloat(SCAN_VTIME_WEIGHT_CONF_KEY, 1.0f);
156   }
157 
158   private String capitalize(final String s) {
159     StringBuilder strBuilder = new StringBuilder(s);
160     strBuilder.setCharAt(0, Character.toUpperCase(strBuilder.charAt(0)));
161     return strBuilder.toString();
162   }
163 
164   /**
165    * Returns a 'priority' based on the request type.
166    *
167    * Currently the returned priority is used for queue selection.
168    * See the SimpleRpcScheduler as example. It maintains a queue per 'priory type'
169    * HIGH_QOS (meta requests), REPLICATION_QOS (replication requests),
170    * NORMAL_QOS (user requests).
171    */
172   @Override
173   public int getPriority(RequestHeader header, Message param, User user) {
174     int priorityByAnnotation = getAnnotatedPriority(header);
175 
176     if (priorityByAnnotation >= 0) {
177       return priorityByAnnotation;
178     }
179     return getBasePriority(header, param);
180   }
181 
182   /**
183    * See if the method has an annotation.
184    * @param header
185    * @return Return the priority from the annotation. If there isn't
186    * an annotation, this returns something below zero.
187    */
188   protected int getAnnotatedPriority(RequestHeader header) {
189     String methodName = header.getMethodName();
190     Integer priorityByAnnotation = annotatedQos.get(methodName);
191     if (priorityByAnnotation != null) {
192       return priorityByAnnotation;
193     }
194     return -1;
195   }
196 
197   /**
198    * Get the priority for a given request from the header and the param
199    * This doesn't consider which user is sending the request at all.
200    * This doesn't consider annotations
201    */
202   protected int getBasePriority(RequestHeader header, Message param) {
203     if (param == null) {
204       return HConstants.NORMAL_QOS;
205     }
206     if (param instanceof MultiRequest) {
207       // The multi call has its priority set in the header.  All calls should work this way but
208       // only this one has been converted so far.  No priority == NORMAL_QOS.
209       return header.hasPriority()? header.getPriority(): HConstants.NORMAL_QOS;
210     }
211 
212     String cls = param.getClass().getName();
213     Class<? extends Message> rpcArgClass = argumentToClassMap.get(cls);
214     RegionSpecifier regionSpecifier = null;
215     //check whether the request has reference to meta region or now.
216     try {
217       // Check if the param has a region specifier; the pb methods are hasRegion and getRegion if
218       // hasRegion returns true.  Not all listed methods have region specifier each time.  For
219       // example, the ScanRequest has it on setup but thereafter relies on the scannerid rather than
220       // send the region over every time.
221       Method hasRegion = methodMap.get("hasRegion").get(rpcArgClass);
222       if (hasRegion != null && (Boolean)hasRegion.invoke(param, (Object[])null)) {
223         Method getRegion = methodMap.get("getRegion").get(rpcArgClass);
224         regionSpecifier = (RegionSpecifier)getRegion.invoke(param, (Object[])null);
225         Region region = rpcServices.getRegion(regionSpecifier);
226         if (region.getRegionInfo().isSystemTable()) {
227           if (LOG.isTraceEnabled()) {
228             LOG.trace("High priority because region=" +
229               region.getRegionInfo().getRegionNameAsString());
230           }
231           return HConstants.SYSTEMTABLE_QOS;
232         }
233       }
234     } catch (Exception ex) {
235       // Not good throwing an exception out of here, a runtime anyways.  Let the query go into the
236       // server and have it throw the exception if still an issue.  Just mark it normal priority.
237       if (LOG.isTraceEnabled()) LOG.trace("Marking normal priority after getting exception=" + ex);
238       return HConstants.NORMAL_QOS;
239     }
240 
241     if (param instanceof ScanRequest) { // scanner methods...
242       ScanRequest request = (ScanRequest)param;
243       if (!request.hasScannerId()) {
244         return HConstants.NORMAL_QOS;
245       }
246       RegionScanner scanner = rpcServices.getScanner(request.getScannerId());
247       if (scanner != null && scanner.getRegionInfo().isSystemTable()) {
248         if (LOG.isTraceEnabled()) {
249           // Scanner requests are small in size so TextFormat version should not overwhelm log.
250           LOG.trace("High priority scanner request " + TextFormat.shortDebugString(request));
251         }
252         return HConstants.SYSTEMTABLE_QOS;
253       }
254     }
255 
256     return HConstants.NORMAL_QOS;
257   }
258 
259   /**
260    * Based on the request content, returns the deadline of the request.
261    *
262    * @param header
263    * @param param
264    * @return Deadline of this request. 0 now, otherwise msec of 'delay'
265    */
266   @Override
267   public long getDeadline(RequestHeader header, Message param) {
268     if (param instanceof ScanRequest) {
269       ScanRequest request = (ScanRequest)param;
270       if (!request.hasScannerId()) {
271         return 0;
272       }
273 
274       // get the 'virtual time' of the scanner, and applies sqrt() to get a
275       // nice curve for the delay. More a scanner is used the less priority it gets.
276       // The weight is used to have more control on the delay.
277       long vtime = rpcServices.getScannerVirtualTime(request.getScannerId());
278       return Math.round(Math.sqrt(vtime * scanVirtualTimeWeight));
279     }
280     return 0;
281   }
282 
283   @VisibleForTesting
284   void setRegionServer(final HRegionServer hrs) {
285     this.rpcServices = hrs.getRSRpcServices();
286   }
287 }