| /* |
| * 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.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators; |
| |
| import java.util.List; |
| |
| import org.apache.commons.math3.random.RandomDataGenerator; |
| import org.apache.hadoop.mapreduce.JobContext; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.POStatus; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.Result; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhyPlanVisitor; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.impl.builtin.PoissonSampleLoader; |
| import org.apache.pig.impl.plan.OperatorKey; |
| import org.apache.pig.impl.plan.VisitorException; |
| import org.apache.pig.impl.util.UDFContext; |
| |
| public class POReservoirSample extends PhysicalOperator { |
| |
| private static final long serialVersionUID = 1L; |
| |
| // number of samples to be sampled |
| protected long numSamples; |
| |
| private transient int nextSampleIdx = 0; |
| |
| private transient long rowProcessed = 0; |
| |
| private transient boolean sampleCollectionDone = false; |
| |
| //array to store the result |
| private transient Result[] samples = null; |
| |
| // last sample result |
| private transient Result lastSample = null; |
| |
| private transient RandomDataGenerator randGen; |
| |
| public POReservoirSample(OperatorKey k) { |
| this(k, -1, null); |
| } |
| |
| public POReservoirSample(OperatorKey k, int rp) { |
| this(k, rp, null); |
| } |
| |
| public POReservoirSample(OperatorKey k, List<PhysicalOperator> inp) { |
| this(k, -1, inp); |
| } |
| |
| public POReservoirSample(OperatorKey k, int rp, List<PhysicalOperator> inp) { |
| super(k, rp, inp); |
| } |
| |
| public POReservoirSample(OperatorKey k, int rp, List<PhysicalOperator> inp, long numSamples) { |
| super(k, rp, inp); |
| this.numSamples = numSamples; |
| } |
| |
| @Override |
| public Tuple illustratorMarkup(Object in, Object out, int eqClassIndex) { |
| // TODO Auto-generated method stub |
| return null; |
| } |
| |
| @Override |
| public void visit(PhyPlanVisitor v) throws VisitorException { |
| v.visitReservoirSample(this); |
| } |
| |
| @Override |
| public Result getNextTuple() throws ExecException { |
| if (sampleCollectionDone){ |
| return getSample(); |
| } |
| //else collect samples |
| if (samples == null) { |
| samples = new Result[(int)numSamples]; |
| long taskIdHashCode = UDFContext.getUDFContext().getJobConf().get(JobContext.TASK_ID).hashCode(); |
| long randomSeed = ((long)taskIdHashCode << 32) | (taskIdHashCode & 0xffffffffL); |
| randGen = new RandomDataGenerator(); |
| randGen.reSeed(randomSeed); |
| } |
| |
| // populate the samples array with first numSamples tuples |
| Result res = null; |
| while (rowProcessed < numSamples) { |
| res = processInput(); |
| if (res.returnStatus == POStatus.STATUS_ERR) { |
| return res; |
| } else if (res.returnStatus == POStatus.STATUS_OK) { |
| samples[(int)rowProcessed] = res; |
| rowProcessed++; |
| } else if (res.returnStatus == POStatus.STATUS_NULL) { |
| continue; |
| } else if (res.returnStatus == POStatus.STATUS_EOP) { |
| if (this.parentPlan.endOfAllInput) { |
| break; |
| } else { |
| // In case of Split can get EOP in between. |
| // Return here instead of setting lastSample to EOP in getSample |
| return res; |
| } |
| } else { |
| break; |
| } |
| } |
| |
| if (res == null || res.returnStatus != POStatus.STATUS_EOP) { |
| while (true) { |
| // pick this as sample |
| res = processInput(); |
| if (res.returnStatus == POStatus.STATUS_ERR) { |
| return res; |
| } else if (res.returnStatus == POStatus.STATUS_NULL) { |
| continue; |
| } else if (res.returnStatus != POStatus.STATUS_OK) { |
| break; |
| } |
| |
| // collect samples until input is exhausted |
| long rand = randGen.nextLong(0, rowProcessed + 1); |
| if (rand < numSamples) { |
| samples[(int)rand] = res; |
| } |
| rowProcessed++; |
| } |
| } |
| |
| if (res.returnStatus == POStatus.STATUS_EOP) { |
| if (this.parentPlan.endOfAllInput) { |
| sampleCollectionDone = true; |
| } else { |
| // In case of Split can get EOP in between. |
| return res; |
| } |
| } |
| |
| return getSample(); |
| } |
| |
| private Result getSample() throws ExecException { |
| if (lastSample == null) { |
| lastSample = retrieveSample(); |
| } |
| if (lastSample.returnStatus==POStatus.STATUS_EOP) { |
| return lastSample; |
| } |
| |
| Result currentSample = retrieveSample(); |
| // If this is the last sample, tag with number of rows |
| if (currentSample.returnStatus == POStatus.STATUS_EOP) { |
| lastSample = createNumRowTuple((Tuple)lastSample.result); |
| } else if (currentSample.returnStatus == POStatus.STATUS_NULL) { |
| return currentSample; |
| } |
| Result result = lastSample; |
| lastSample = currentSample; |
| return result; |
| } |
| |
| private Result retrieveSample() throws ExecException { |
| if(nextSampleIdx < Math.min(rowProcessed, samples.length)){ |
| if (illustrator != null) { |
| illustratorMarkup(samples[nextSampleIdx].result, samples[nextSampleIdx].result, 0); |
| } |
| Result res = samples[nextSampleIdx]; |
| samples[nextSampleIdx++] = null; //Free memory |
| if (res == null) { // Input data has lesser rows than numSamples |
| return RESULT_EMPTY; |
| } |
| return res; |
| } |
| else{ |
| samples = null; // Free memory |
| return RESULT_EOP; |
| } |
| } |
| |
| @Override |
| public boolean supportsMultipleInputs() { |
| return false; |
| } |
| |
| @Override |
| public boolean supportsMultipleOutputs() { |
| return false; |
| } |
| |
| @Override |
| public String name() { |
| return getAliasString() + "ReservoirSample - " + mKey.toString(); |
| } |
| |
| /** |
| * @param sample - sample tuple |
| * @return - Tuple appended with special marker string column, num-rows column |
| * @throws ExecException |
| */ |
| private Result createNumRowTuple(Tuple sample) throws ExecException { |
| int sz = (sample == null) ? 0 : sample.size(); |
| Tuple t = mTupleFactory.newTuple(sz + 2); |
| |
| if (sample != null) { |
| for (int i=0; i<sample.size(); i++){ |
| t.set(i, sample.get(i)); |
| } |
| } |
| |
| t.set(sz, PoissonSampleLoader.NUMROWS_TUPLE_MARKER); |
| t.set(sz + 1, rowProcessed); |
| return new Result(POStatus.STATUS_OK, t); |
| } |
| |
| } |