/* This file is part of VoltDB.
* Copyright (C) 2008-2017 VoltDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with VoltDB. If not, see <http://www.gnu.org/licenses/>.
*/
package org.voltdb;
import java.util.ArrayList;
import java.util.Iterator;
import org.voltdb.VoltTable.ColumnInfo;
/**
* A class to track and generate statistics regarding task starvation.
* A worker thread can instantiate one of these and report when starvation begins and ends.
*/
public class StarvationTracker extends SiteStatsSource {
public StarvationTracker(long siteId) {
super(siteId, false);
m_lastStartTime = m_startTime = System.nanoTime();
}
/*
* Keep track of the time since the tracker was created or in the interval case, the last time
* the stat was checked
*/
private long m_startTime;
private long m_lastStartTime;
private long m_count = 0;
private long m_lastCount = 0;
private long m_sumOfSquares = 0;
private long m_lastSumOfSquares = 0;
private long m_totalTime = 0;
private long m_lastTotalTime = 0;
private long m_max = 0;
private long m_lastMax = 0;
private long m_min = Long.MAX_VALUE;
private long m_lastMin = Long.MAX_VALUE;
private long m_starvationStartTime;
private boolean m_interval;
/**
* Is there currently starvation
*/
private boolean m_starved = false;
public void beginStarvation() {
if (m_starved) {
return;
}
m_starved = true;
m_starvationStartTime = System.nanoTime();
}
public void endStarvation() {
if (!m_starved) {
return;
}
m_starved = false;
m_count++;
long delta = System.nanoTime() - m_starvationStartTime;
m_totalTime += delta;
m_sumOfSquares += delta * delta / 1000000;
m_max = Math.max(m_max, delta);
m_lastMax = Math.max(m_lastMax, delta);
m_min = Math.min(m_min, delta);
m_lastMin = Math.min(m_lastMin, delta);
}
@Override
protected void populateColumnSchema(ArrayList<ColumnInfo> columns) {
super.populateColumnSchema(columns);
columns.add(new ColumnInfo("COUNT", VoltType.BIGINT));
columns.add(new ColumnInfo("PERCENT", VoltType.FLOAT));
columns.add(new ColumnInfo("AVG", VoltType.BIGINT));
columns.add(new ColumnInfo("MIN", VoltType.BIGINT));
columns.add(new ColumnInfo("MAX", VoltType.BIGINT));
columns.add(new ColumnInfo("STDDEV", VoltType.BIGINT));
}
@Override
protected void updateStatsRow(Object rowKey, Object rowValues[]) {
if (m_interval) {
final long now = System.nanoTime();
final long totalTime = now - m_lastStartTime;
final long count = m_count - m_lastCount;
final long totalStarvedTime = m_totalTime - m_lastTotalTime;
final long sumOfSquares = m_sumOfSquares - m_lastSumOfSquares;
final long uSecs = totalStarvedTime / 1000;
m_lastStartTime = now;
m_lastSumOfSquares = m_sumOfSquares;
m_lastTotalTime = m_totalTime;
m_lastCount = m_count;
m_lastMax = 0;
m_lastMin = Long.MAX_VALUE;
if (count > 0) {
rowValues[columnNameToIndex.get("COUNT")] = count;
rowValues[columnNameToIndex.get("PERCENT")] = totalStarvedTime / (totalTime / 100.0);
rowValues[columnNameToIndex.get("AVG")] = (totalStarvedTime / count) / 1000;
rowValues[columnNameToIndex.get("MIN")] = m_lastMin;
rowValues[columnNameToIndex.get("MAX")] = m_lastMax;
rowValues[columnNameToIndex.get("STDDEV")] = (long)Math.sqrt(sumOfSquares / count - uSecs * uSecs);
} else {
rowValues[columnNameToIndex.get("COUNT")] = 0L;
rowValues[columnNameToIndex.get("PERCENT")] = 0L;
rowValues[columnNameToIndex.get("AVG")] = 0L;
rowValues[columnNameToIndex.get("MIN")] = 0L;
rowValues[columnNameToIndex.get("MAX")] = 0L;
rowValues[columnNameToIndex.get("STDDEV")] = 0L;
}
} else {
final long totalTime = System.nanoTime() - m_startTime;
if (m_count > 0) {
final long uSecs = (m_totalTime / m_count) / 1000;
rowValues[columnNameToIndex.get("COUNT")] = m_count;
rowValues[columnNameToIndex.get("PERCENT")] = m_totalTime / (totalTime / 100.0);
rowValues[columnNameToIndex.get("AVG")] = uSecs;
rowValues[columnNameToIndex.get("MIN")] = m_min;
rowValues[columnNameToIndex.get("MAX")] = m_max;
rowValues[columnNameToIndex.get("STDDEV")] = (long)Math.sqrt(m_sumOfSquares / m_count - uSecs * uSecs);
}
else {
rowValues[columnNameToIndex.get("COUNT")] = 0L;
rowValues[columnNameToIndex.get("PERCENT")] = 0L;
rowValues[columnNameToIndex.get("AVG")] = 0L;
rowValues[columnNameToIndex.get("MIN")] = 0L;
rowValues[columnNameToIndex.get("MAX")] = 0L;
rowValues[columnNameToIndex.get("STDDEV")] = 0L;
}
}
super.updateStatsRow(rowKey, rowValues);
}
@Override
protected Iterator<Object> getStatsRowKeyIterator(final boolean interval) {
m_interval = interval;
return new Iterator<Object>() {
boolean returnRow = true;
@Override
public boolean hasNext() {
return returnRow;
}
@Override
public Object next() {
if (returnRow) {
returnRow = false;
return new Object();
} else {
return null;
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
}