/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hbase.regionserver;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.NotServingRegionException;
import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.CloseRegionRequest;
import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.CompactRegionRequest;
import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.FlushRegionRequest;
import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.GetRegionInfoRequest;
import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.GetStoreFileRequest;
import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.SplitRegionRequest;
import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.GetRequest;
import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MultiRequest;
import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MutateRequest;
import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ScanRequest;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.RegionSpecifier;
import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.RequestHeader;
import org.apache.hadoop.hbase.regionserver.HRegionServer.QosPriority;
import org.apache.hadoop.hbase.util.Pair;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Function;
import com.google.protobuf.Message;
import com.google.protobuf.TextFormat;
/**
* A guava function that will return a priority for use by QoS facility in regionserver; e.g.
* rpcs to .META. and -ROOT-, etc., get priority.
*/
// TODO: Remove. This is doing way too much work just to figure a priority. Do as Elliott
// suggests and just have the client specify a priority.
//The logic for figuring out high priority RPCs is as follows:
//1. if the method is annotated with a QosPriority of QOS_HIGH,
// that is honored
//2. parse out the protobuf message and see if the request is for meta
// region, and if so, treat it as a high priority RPC
//Some optimizations for (2) are done here -
//Clients send the argument classname as part of making the RPC. The server
//decides whether to deserialize the proto argument message based on the
//pre-established set of argument classes (knownArgumentClasses below).
//This prevents the server from having to deserialize all proto argument
//messages prematurely.
//All the argument classes declare a 'getRegion' method that returns a
//RegionSpecifier object. Methods can be invoked on the returned object
//to figure out whether it is a meta region or not.
class QosFunction implements Function<Pair<RequestHeader, Message>, Integer> {
public static final Log LOG = LogFactory.getLog(QosFunction.class.getName());
private final Map<String, Integer> annotatedQos;
//We need to mock the regionserver instance for some unit tests (set via
//setRegionServer method.
private HRegionServer hRegionServer;
@SuppressWarnings("unchecked")
private final Class<? extends Message>[] knownArgumentClasses = new Class[]{
GetRegionInfoRequest.class,
GetStoreFileRequest.class,
CloseRegionRequest.class,
FlushRegionRequest.class,
SplitRegionRequest.class,
CompactRegionRequest.class,
GetRequest.class,
MutateRequest.class,
ScanRequest.class,
MultiRequest.class
};
// Some caches for helping performance
private final Map<String, Class<? extends Message>> argumentToClassMap =
new HashMap<String, Class<? extends Message>>();
private final Map<String, Map<Class<? extends Message>, Method>> methodMap =
new HashMap<String, Map<Class<? extends Message>, Method>>();
QosFunction(final HRegionServer hrs) {
this.hRegionServer = hrs;
Map<String, Integer> qosMap = new HashMap<String, Integer>();
for (Method m : HRegionServer.class.getMethods()) {
QosPriority p = m.getAnnotation(QosPriority.class);
if (p != null) {
qosMap.put(m.getName(), p.priority());
}
}
this.annotatedQos = qosMap;
if (methodMap.get("getRegion") == null) {
methodMap.put("hasRegion", new HashMap<Class<? extends Message>, Method>());
methodMap.put("getRegion", new HashMap<Class<? extends Message>, Method>());
}
for (Class<? extends Message> cls : knownArgumentClasses) {
argumentToClassMap.put(cls.getName(), cls);
try {
methodMap.get("hasRegion").put(cls, cls.getDeclaredMethod("hasRegion"));
methodMap.get("getRegion").put(cls, cls.getDeclaredMethod("getRegion"));
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
public boolean isMetaRegion(byte[] regionName) {
HRegion region;
try {
region = hRegionServer.getRegion(regionName);
} catch (NotServingRegionException ignored) {
return false;
}
return region.getRegionInfo().isMetaTable();
}
@Override
public Integer apply(Pair<RequestHeader, Message> headerAndParam) {
RequestHeader header = headerAndParam.getFirst();
String methodName = header.getMethodName();
Integer priorityByAnnotation = annotatedQos.get(header.getMethodName());
if (priorityByAnnotation != null) {
return priorityByAnnotation;
}
Message param = headerAndParam.getSecond();
if (param == null) {
return HConstants.NORMAL_QOS;
}
String cls = param.getClass().getName();
Class<? extends Message> rpcArgClass = argumentToClassMap.get(cls);
RegionSpecifier regionSpecifier = null;
//check whether the request has reference to meta region or now.
try {
// Check if the param has a region specifier; the pb methods are hasRegion and getRegion if
// hasRegion returns true. Not all listed methods have region specifier each time. For
// example, the ScanRequest has it on setup but thereafter relies on the scannerid rather than
// send the region over every time.
Method hasRegion = methodMap.get("hasRegion").get(rpcArgClass);
if (hasRegion != null && (Boolean)hasRegion.invoke(param, (Object[])null)) {
Method getRegion = methodMap.get("getRegion").get(rpcArgClass);
regionSpecifier = (RegionSpecifier)getRegion.invoke(param, (Object[])null);
HRegion region = hRegionServer.getRegion(regionSpecifier);
if (region.getRegionInfo().isMetaTable()) {
if (LOG.isTraceEnabled()) {
LOG.trace("High priority because region=" + region.getRegionNameAsString());
}
return HConstants.HIGH_QOS;
}
}
} catch (Exception ex) {
// Not good throwing an exception out of here, a runtime anyways. Let the query go into the
// server and have it throw the exception if still an issue. Just mark it normal priority.
if (LOG.isTraceEnabled()) LOG.trace("Marking normal priority after getting exception=" + ex);
return HConstants.NORMAL_QOS;
}
if (methodName.equals("scan")) { // scanner methods...
ScanRequest request = (ScanRequest)param;
if (!request.hasScannerId()) {
return HConstants.NORMAL_QOS;
}
RegionScanner scanner = hRegionServer.getScanner(request.getScannerId());
if (scanner != null && scanner.getRegionInfo().isMetaRegion()) {
if (LOG.isTraceEnabled()) {
// Scanner requests are small in size so TextFormat version should not overwhelm log.
LOG.trace("High priority scanner request " + TextFormat.shortDebugString(request));
}
return HConstants.HIGH_QOS;
}
}
return HConstants.NORMAL_QOS;
}
@VisibleForTesting
void setRegionServer(final HRegionServer hrs) {
this.hRegionServer = hrs;
}
}