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* Licensed to the Apache Software Foundation (ASF) under one
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* 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
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* KIND, either express or implied. See the License for the
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package org.apache.hadoop.hive.metastore.columnstats.aggr;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.apache.hadoop.hive.common.ndv.NumDistinctValueEstimator;
import org.apache.hadoop.hive.common.ndv.NumDistinctValueEstimatorFactory;
import org.apache.hadoop.hive.metastore.api.ColumnStatisticsData;
import org.apache.hadoop.hive.metastore.api.ColumnStatisticsObj;
import org.apache.hadoop.hive.metastore.api.DecimalColumnStatsData;
import org.apache.hadoop.hive.metastore.api.MetaException;
import org.apache.hadoop.hive.metastore.api.utils.DecimalUtils;
import org.apache.hadoop.hive.metastore.columnstats.cache.DecimalColumnStatsDataInspector;
import org.apache.hadoop.hive.metastore.columnstats.merge.DecimalColumnStatsMerger;
import org.apache.hadoop.hive.metastore.utils.MetaStoreServerUtils;
import org.apache.hadoop.hive.metastore.utils.MetaStoreServerUtils.ColStatsObjWithSourceInfo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static org.apache.hadoop.hive.metastore.columnstats.ColumnsStatsUtils.decimalInspectorFromStats;
public class DecimalColumnStatsAggregator extends ColumnStatsAggregator implements
IExtrapolatePartStatus {
private static final Logger LOG = LoggerFactory.getLogger(DecimalColumnStatsAggregator.class);
@Override
public ColumnStatisticsObj aggregate(List<ColStatsObjWithSourceInfo> colStatsWithSourceInfo,
List<String> partNames, boolean areAllPartsFound) throws MetaException {
ColumnStatisticsObj statsObj = null;
String colType = null;
String colName = null;
// check if all the ColumnStatisticsObjs contain stats and all the ndv are
// bitvectors
boolean doAllPartitionContainStats = partNames.size() == colStatsWithSourceInfo.size();
NumDistinctValueEstimator ndvEstimator = null;
for (ColStatsObjWithSourceInfo csp : colStatsWithSourceInfo) {
ColumnStatisticsObj cso = csp.getColStatsObj();
if (statsObj == null) {
colName = cso.getColName();
colType = cso.getColType();
statsObj = ColumnStatsAggregatorFactory.newColumnStaticsObj(colName, colType,
cso.getStatsData().getSetField());
LOG.trace("doAllPartitionContainStats for column: {} is: {}", colName,
doAllPartitionContainStats);
}
DecimalColumnStatsDataInspector decimalColumnStatsData = decimalInspectorFromStats(cso);
if (decimalColumnStatsData.getNdvEstimator() == null) {
ndvEstimator = null;
break;
} else {
// check if all of the bit vectors can merge
NumDistinctValueEstimator estimator = decimalColumnStatsData.getNdvEstimator();
if (ndvEstimator == null) {
ndvEstimator = estimator;
} else {
if (ndvEstimator.canMerge(estimator)) {
continue;
} else {
ndvEstimator = null;
break;
}
}
}
}
if (ndvEstimator != null) {
ndvEstimator = NumDistinctValueEstimatorFactory
.getEmptyNumDistinctValueEstimator(ndvEstimator);
}
LOG.debug("all of the bit vectors can merge for " + colName + " is " + (ndvEstimator != null));
ColumnStatisticsData columnStatisticsData = new ColumnStatisticsData();
if (doAllPartitionContainStats || colStatsWithSourceInfo.size() < 2) {
DecimalColumnStatsDataInspector aggregateData = null;
long lowerBound = 0;
long higherBound = 0;
double densityAvgSum = 0.0;
for (ColStatsObjWithSourceInfo csp : colStatsWithSourceInfo) {
ColumnStatisticsObj cso = csp.getColStatsObj();
DecimalColumnStatsDataInspector newData = decimalInspectorFromStats(cso);
lowerBound = Math.max(lowerBound, newData.getNumDVs());
higherBound += newData.getNumDVs();
if (newData.isSetLowValue() && newData.isSetHighValue()) {
densityAvgSum += (MetaStoreServerUtils.decimalToDouble(newData.getHighValue()) - MetaStoreServerUtils
.decimalToDouble(newData.getLowValue())) / newData.getNumDVs();
}
if (ndvEstimator != null) {
ndvEstimator.mergeEstimators(newData.getNdvEstimator());
}
if (aggregateData == null) {
aggregateData = newData.deepCopy();
} else {
DecimalColumnStatsMerger merger = new DecimalColumnStatsMerger();
merger.setLowValue(aggregateData, newData);
merger.setHighValue(aggregateData, newData);
aggregateData.setNumNulls(aggregateData.getNumNulls() + newData.getNumNulls());
aggregateData.setNumDVs(Math.max(aggregateData.getNumDVs(), newData.getNumDVs()));
}
}
if (ndvEstimator != null) {
// if all the ColumnStatisticsObjs contain bitvectors, we do not need to
// use uniform distribution assumption because we can merge bitvectors
// to get a good estimation.
aggregateData.setNumDVs(ndvEstimator.estimateNumDistinctValues());
} else {
long estimation;
if (useDensityFunctionForNDVEstimation) {
// We have estimation, lowerbound and higherbound. We use estimation
// if it is between lowerbound and higherbound.
double densityAvg = densityAvgSum / partNames.size();
estimation = (long) ((MetaStoreServerUtils.decimalToDouble(aggregateData.getHighValue()) - MetaStoreServerUtils
.decimalToDouble(aggregateData.getLowValue())) / densityAvg);
if (estimation < lowerBound) {
estimation = lowerBound;
} else if (estimation > higherBound) {
estimation = higherBound;
}
} else {
estimation = (long) (lowerBound + (higherBound - lowerBound) * ndvTuner);
}
aggregateData.setNumDVs(estimation);
}
columnStatisticsData.setDecimalStats(aggregateData);
} else {
// we need extrapolation
LOG.debug("start extrapolation for " + colName);
Map<String, Integer> indexMap = new HashMap<>();
for (int index = 0; index < partNames.size(); index++) {
indexMap.put(partNames.get(index), index);
}
Map<String, Double> adjustedIndexMap = new HashMap<>();
Map<String, ColumnStatisticsData> adjustedStatsMap = new HashMap<>();
// while we scan the css, we also get the densityAvg, lowerbound and
// higerbound when useDensityFunctionForNDVEstimation is true.
double densityAvgSum = 0.0;
if (ndvEstimator == null) {
// if not every partition uses bitvector for ndv, we just fall back to
// the traditional extrapolation methods.
for (ColStatsObjWithSourceInfo csp : colStatsWithSourceInfo) {
ColumnStatisticsObj cso = csp.getColStatsObj();
String partName = csp.getPartName();
DecimalColumnStatsData newData = cso.getStatsData().getDecimalStats();
if (useDensityFunctionForNDVEstimation) {
densityAvgSum += (MetaStoreServerUtils.decimalToDouble(newData.getHighValue()) - MetaStoreServerUtils
.decimalToDouble(newData.getLowValue())) / newData.getNumDVs();
}
adjustedIndexMap.put(partName, (double) indexMap.get(partName));
adjustedStatsMap.put(partName, cso.getStatsData());
}
} else {
// we first merge all the adjacent bitvectors that we could merge and
// derive new partition names and index.
StringBuilder pseudoPartName = new StringBuilder();
double pseudoIndexSum = 0;
int length = 0;
int curIndex = -1;
DecimalColumnStatsDataInspector aggregateData = null;
for (ColStatsObjWithSourceInfo csp : colStatsWithSourceInfo) {
ColumnStatisticsObj cso = csp.getColStatsObj();
String partName = csp.getPartName();
DecimalColumnStatsDataInspector newData = decimalInspectorFromStats(cso);
// newData.isSetBitVectors() should be true for sure because we
// already checked it before.
if (indexMap.get(partName) != curIndex) {
// There is bitvector, but it is not adjacent to the previous ones.
if (length > 0) {
// we have to set ndv
adjustedIndexMap.put(pseudoPartName.toString(), pseudoIndexSum / length);
aggregateData.setNumDVs(ndvEstimator.estimateNumDistinctValues());
ColumnStatisticsData csd = new ColumnStatisticsData();
csd.setDecimalStats(aggregateData);
adjustedStatsMap.put(pseudoPartName.toString(), csd);
if (useDensityFunctionForNDVEstimation) {
densityAvgSum += (MetaStoreServerUtils.decimalToDouble(aggregateData.getHighValue()) - MetaStoreServerUtils
.decimalToDouble(aggregateData.getLowValue())) / aggregateData.getNumDVs();
}
// reset everything
pseudoPartName = new StringBuilder();
pseudoIndexSum = 0;
length = 0;
ndvEstimator = NumDistinctValueEstimatorFactory.getEmptyNumDistinctValueEstimator(ndvEstimator);
}
aggregateData = null;
}
curIndex = indexMap.get(partName);
pseudoPartName.append(partName);
pseudoIndexSum += curIndex;
length++;
curIndex++;
if (aggregateData == null) {
aggregateData = newData.deepCopy();
} else {
if (MetaStoreServerUtils.decimalToDouble(aggregateData.getLowValue()) < MetaStoreServerUtils
.decimalToDouble(newData.getLowValue())) {
aggregateData.setLowValue(aggregateData.getLowValue());
} else {
aggregateData.setLowValue(newData.getLowValue());
}
if (MetaStoreServerUtils.decimalToDouble(aggregateData.getHighValue()) > MetaStoreServerUtils
.decimalToDouble(newData.getHighValue())) {
aggregateData.setHighValue(aggregateData.getHighValue());
} else {
aggregateData.setHighValue(newData.getHighValue());
}
aggregateData.setNumNulls(aggregateData.getNumNulls() + newData.getNumNulls());
}
ndvEstimator.mergeEstimators(newData.getNdvEstimator());
}
if (length > 0) {
// we have to set ndv
adjustedIndexMap.put(pseudoPartName.toString(), pseudoIndexSum / length);
aggregateData.setNumDVs(ndvEstimator.estimateNumDistinctValues());
ColumnStatisticsData csd = new ColumnStatisticsData();
csd.setDecimalStats(aggregateData);
adjustedStatsMap.put(pseudoPartName.toString(), csd);
if (useDensityFunctionForNDVEstimation) {
densityAvgSum += (MetaStoreServerUtils.decimalToDouble(aggregateData.getHighValue()) - MetaStoreServerUtils
.decimalToDouble(aggregateData.getLowValue())) / aggregateData.getNumDVs();
}
}
}
extrapolate(columnStatisticsData, partNames.size(), colStatsWithSourceInfo.size(),
adjustedIndexMap, adjustedStatsMap, densityAvgSum / adjustedStatsMap.size());
}
LOG.debug(
"Ndv estimatation for {} is {} # of partitions requested: {} # of partitions found: {}",
colName, columnStatisticsData.getDecimalStats().getNumDVs(), partNames.size(),
colStatsWithSourceInfo.size());
statsObj.setStatsData(columnStatisticsData);
return statsObj;
}
@Override
public void extrapolate(ColumnStatisticsData extrapolateData, int numParts,
int numPartsWithStats, Map<String, Double> adjustedIndexMap,
Map<String, ColumnStatisticsData> adjustedStatsMap, double densityAvg) {
int rightBorderInd = numParts;
DecimalColumnStatsDataInspector extrapolateDecimalData = new DecimalColumnStatsDataInspector();
Map<String, DecimalColumnStatsData> extractedAdjustedStatsMap = new HashMap<>();
for (Map.Entry<String, ColumnStatisticsData> entry : adjustedStatsMap.entrySet()) {
extractedAdjustedStatsMap.put(entry.getKey(), entry.getValue().getDecimalStats());
}
List<Map.Entry<String, DecimalColumnStatsData>> list = new LinkedList<>(
extractedAdjustedStatsMap.entrySet());
// get the lowValue
Collections.sort(list, new Comparator<Map.Entry<String, DecimalColumnStatsData>>() {
@Override
public int compare(Map.Entry<String, DecimalColumnStatsData> o1,
Map.Entry<String, DecimalColumnStatsData> o2) {
return o1.getValue().getLowValue().compareTo(o2.getValue().getLowValue());
}
});
double minInd = adjustedIndexMap.get(list.get(0).getKey());
double maxInd = adjustedIndexMap.get(list.get(list.size() - 1).getKey());
double lowValue = 0;
double min = MetaStoreServerUtils.decimalToDouble(list.get(0).getValue().getLowValue());
double max = MetaStoreServerUtils.decimalToDouble(list.get(list.size() - 1).getValue().getLowValue());
if (minInd == maxInd) {
lowValue = min;
} else if (minInd < maxInd) {
// left border is the min
lowValue = (max - (max - min) * maxInd / (maxInd - minInd));
} else {
// right border is the min
lowValue = (max - (max - min) * (rightBorderInd - maxInd) / (minInd - maxInd));
}
// get the highValue
Collections.sort(list, new Comparator<Map.Entry<String, DecimalColumnStatsData>>() {
@Override
public int compare(Map.Entry<String, DecimalColumnStatsData> o1,
Map.Entry<String, DecimalColumnStatsData> o2) {
return o1.getValue().getHighValue().compareTo(o2.getValue().getHighValue());
}
});
minInd = adjustedIndexMap.get(list.get(0).getKey());
maxInd = adjustedIndexMap.get(list.get(list.size() - 1).getKey());
double highValue = 0;
min = MetaStoreServerUtils.decimalToDouble(list.get(0).getValue().getHighValue());
max = MetaStoreServerUtils.decimalToDouble(list.get(list.size() - 1).getValue().getHighValue());
if (minInd == maxInd) {
highValue = min;
} else if (minInd < maxInd) {
// right border is the max
highValue = (min + (max - min) * (rightBorderInd - minInd) / (maxInd - minInd));
} else {
// left border is the max
highValue = (min + (max - min) * minInd / (minInd - maxInd));
}
// get the #nulls
long numNulls = 0;
for (Map.Entry<String, DecimalColumnStatsData> entry : extractedAdjustedStatsMap.entrySet()) {
numNulls += entry.getValue().getNumNulls();
}
// we scale up sumNulls based on the number of partitions
numNulls = numNulls * numParts / numPartsWithStats;
// get the ndv
long ndv = 0;
long ndvMin = 0;
long ndvMax = 0;
Collections.sort(list, new Comparator<Map.Entry<String, DecimalColumnStatsData>>() {
@Override
public int compare(Map.Entry<String, DecimalColumnStatsData> o1,
Map.Entry<String, DecimalColumnStatsData> o2) {
return Long.compare(o1.getValue().getNumDVs(), o2.getValue().getNumDVs());
}
});
long lowerBound = list.get(list.size() - 1).getValue().getNumDVs();
long higherBound = 0;
for (Map.Entry<String, DecimalColumnStatsData> entry : list) {
higherBound += entry.getValue().getNumDVs();
}
if (useDensityFunctionForNDVEstimation && densityAvg != 0.0) {
ndv = (long) ((highValue - lowValue) / densityAvg);
if (ndv < lowerBound) {
ndv = lowerBound;
} else if (ndv > higherBound) {
ndv = higherBound;
}
} else {
minInd = adjustedIndexMap.get(list.get(0).getKey());
maxInd = adjustedIndexMap.get(list.get(list.size() - 1).getKey());
ndvMin = list.get(0).getValue().getNumDVs();
ndvMax = list.get(list.size() - 1).getValue().getNumDVs();
if (minInd == maxInd) {
ndv = ndvMin;
} else if (minInd < maxInd) {
// right border is the max
ndv = (long) (ndvMin + (ndvMax - ndvMin) * (rightBorderInd - minInd) / (maxInd - minInd));
} else {
// left border is the max
ndv = (long) (ndvMin + (ndvMax - ndvMin) * minInd / (minInd - maxInd));
}
}
extrapolateDecimalData.setLowValue(DecimalUtils.createThriftDecimal(String
.valueOf(lowValue)));
extrapolateDecimalData.setHighValue(DecimalUtils.createThriftDecimal(String
.valueOf(highValue)));
extrapolateDecimalData.setNumNulls(numNulls);
extrapolateDecimalData.setNumDVs(ndv);
extrapolateData.setDecimalStats(extrapolateDecimalData);
}
}