org.apache.hadoop.hive.ql.plan.ReducerTimeStatsPerJob Maven / Gradle / Ivy
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* 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.hive.ql.plan;
import java.util.List;
/*
* Encapsulates statistics about the duration of all reduce tasks
* corresponding to a specific JobId.
* The stats are computed in the HadoopJobExecHelper when the
* job completes and then populated inside the QueryPlan for
* each job, from where it can be later on accessed.
* The reducer statistics consist of minimum/maximum/mean/stdv of the
* run times of all the reduce tasks for a job. All the Run times are
* in Milliseconds.
*/
public class ReducerTimeStatsPerJob {
// Stores the temporal statistics in milliseconds for reducers
// specific to a Job
private final long minimumTime;
private final long maximumTime;
private final double meanTime;
private final double standardDeviationTime;
/*
* Computes the temporal run time statistics of the reducers
* for a specific JobId.
*/
public ReducerTimeStatsPerJob(List reducersRunTimes) {
// If no Run times present, then set -1, indicating no values
if (!reducersRunTimes.isEmpty()) {
long minimumTime = reducersRunTimes.get(0);
long maximumTime = reducersRunTimes.get(0);
long totalTime = reducersRunTimes.get(0);
double standardDeviationTime = 0.0;
double meanTime = 0.0;
for (int i = 1; i < reducersRunTimes.size(); i++) {
if (reducersRunTimes.get(i) < minimumTime) {
minimumTime = reducersRunTimes.get(i);
}
if (reducersRunTimes.get(i) > maximumTime) {
maximumTime = reducersRunTimes.get(i);
}
totalTime += reducersRunTimes.get(i);
}
meanTime = (double) totalTime / reducersRunTimes.size();
for (int i = 0; i < reducersRunTimes.size(); i++) {
standardDeviationTime += Math.pow(meanTime - reducersRunTimes.get(i), 2);
}
standardDeviationTime /= reducersRunTimes.size();
standardDeviationTime = Math.sqrt(standardDeviationTime);
this.minimumTime = minimumTime;
this.maximumTime = maximumTime;
this.meanTime = meanTime;
this.standardDeviationTime = standardDeviationTime;
return;
}
this.minimumTime = -1;
this.maximumTime = -1;
this.meanTime = -1.0;
this.standardDeviationTime = -1.0;
return;
}
public long getMinimumTime() {
return this.minimumTime;
}
public long getMaximumTime() {
return this.maximumTime;
}
public double getMeanTime() {
return this.meanTime;
}
public double getStandardDeviationTime() {
return this.standardDeviationTime;
}
}