Examples with DecimalColumnStatsData org.apache.hadoop.hive.metastore.api.DecimalColumnStatsData used on opensource projects

Example 16 with DecimalColumnStatsData

use of org.apache.hadoop.hive.metastore.api.DecimalColumnStatsData in project hive by apache.

the class TestHBaseStoreIntegration method tableStatistics.

@Test
public void tableStatistics() throws Exception {
    long now = System.currentTimeMillis();
    String dbname = "default";
    String tableName = "statstable";
    String boolcol = "boolcol";
    String longcol = "longcol";
    String doublecol = "doublecol";
    String stringcol = "stringcol";
    String binarycol = "bincol";
    String decimalcol = "deccol";
    long trues = 37;
    long falses = 12;
    long booleanNulls = 2;
    long longHigh = 120938479124L;
    long longLow = -12341243213412124L;
    long longNulls = 23;
    long longDVs = 213L;
    double doubleHigh = 123423.23423;
    double doubleLow = 0.00001234233;
    long doubleNulls = 92;
    long doubleDVs = 1234123421L;
    long strMaxLen = 1234;
    double strAvgLen = 32.3;
    long strNulls = 987;
    long strDVs = 906;
    long binMaxLen = 123412987L;
    double binAvgLen = 76.98;
    long binNulls = 976998797L;
    Decimal decHigh = new Decimal();
    decHigh.setScale((short) 3);
    // I have no clue how this is translated, but it
    decHigh.setUnscaled("3876".getBytes());
    // doesn't matter
    Decimal decLow = new Decimal();
    decLow.setScale((short) 3);
    decLow.setUnscaled("38".getBytes());
    long decNulls = 13;
    long decDVs = 923947293L;
    List<FieldSchema> cols = new ArrayList<FieldSchema>();
    cols.add(new FieldSchema(boolcol, "boolean", "nocomment"));
    cols.add(new FieldSchema(longcol, "long", "nocomment"));
    cols.add(new FieldSchema(doublecol, "double", "nocomment"));
    cols.add(new FieldSchema(stringcol, "varchar(32)", "nocomment"));
    cols.add(new FieldSchema(binarycol, "binary", "nocomment"));
    cols.add(new FieldSchema(decimalcol, "decimal(5, 3)", "nocomment"));
    SerDeInfo serde = new SerDeInfo("serde", "seriallib", null);
    StorageDescriptor sd = new StorageDescriptor(cols, "file:/tmp", "input", "output", false, 0, serde, null, null, emptyParameters);
    Table table = new Table(tableName, dbname, "me", (int) now / 1000, (int) now / 1000, 0, sd, null, emptyParameters, null, null, null);
    store.createTable(table);
    ColumnStatistics stats = new ColumnStatistics();
    ColumnStatisticsDesc desc = new ColumnStatisticsDesc();
    desc.setLastAnalyzed(now);
    desc.setDbName(dbname);
    desc.setTableName(tableName);
    desc.setIsTblLevel(true);
    stats.setStatsDesc(desc);
    // Do one column of each type
    ColumnStatisticsObj obj = new ColumnStatisticsObj();
    obj.setColName(boolcol);
    obj.setColType("boolean");
    ColumnStatisticsData data = new ColumnStatisticsData();
    BooleanColumnStatsData boolData = new BooleanColumnStatsData();
    boolData.setNumTrues(trues);
    boolData.setNumFalses(falses);
    boolData.setNumNulls(booleanNulls);
    data.setBooleanStats(boolData);
    obj.setStatsData(data);
    stats.addToStatsObj(obj);
    obj = new ColumnStatisticsObj();
    obj.setColName(longcol);
    obj.setColType("long");
    data = new ColumnStatisticsData();
    LongColumnStatsData longData = new LongColumnStatsData();
    longData.setHighValue(longHigh);
    longData.setLowValue(longLow);
    longData.setNumNulls(longNulls);
    longData.setNumDVs(longDVs);
    data.setLongStats(longData);
    obj.setStatsData(data);
    stats.addToStatsObj(obj);
    obj = new ColumnStatisticsObj();
    obj.setColName(doublecol);
    obj.setColType("double");
    data = new ColumnStatisticsData();
    DoubleColumnStatsData doubleData = new DoubleColumnStatsData();
    doubleData.setHighValue(doubleHigh);
    doubleData.setLowValue(doubleLow);
    doubleData.setNumNulls(doubleNulls);
    doubleData.setNumDVs(doubleDVs);
    data.setDoubleStats(doubleData);
    obj.setStatsData(data);
    stats.addToStatsObj(obj);
    store.updateTableColumnStatistics(stats);
    stats = store.getTableColumnStatistics(dbname, tableName, Arrays.asList(boolcol, longcol, doublecol));
    // We'll check all of the individual values later.
    Assert.assertEquals(3, stats.getStatsObjSize());
    // check that we can fetch just some of the columns
    stats = store.getTableColumnStatistics(dbname, tableName, Arrays.asList(boolcol));
    Assert.assertEquals(1, stats.getStatsObjSize());
    stats = new ColumnStatistics();
    stats.setStatsDesc(desc);
    obj = new ColumnStatisticsObj();
    obj.setColName(stringcol);
    obj.setColType("string");
    data = new ColumnStatisticsData();
    StringColumnStatsData strData = new StringColumnStatsData();
    strData.setMaxColLen(strMaxLen);
    strData.setAvgColLen(strAvgLen);
    strData.setNumNulls(strNulls);
    strData.setNumDVs(strDVs);
    data.setStringStats(strData);
    obj.setStatsData(data);
    stats.addToStatsObj(obj);
    obj = new ColumnStatisticsObj();
    obj.setColName(binarycol);
    obj.setColType("binary");
    data = new ColumnStatisticsData();
    BinaryColumnStatsData binData = new BinaryColumnStatsData();
    binData.setMaxColLen(binMaxLen);
    binData.setAvgColLen(binAvgLen);
    binData.setNumNulls(binNulls);
    data.setBinaryStats(binData);
    obj.setStatsData(data);
    stats.addToStatsObj(obj);
    obj = new ColumnStatisticsObj();
    obj.setColName(decimalcol);
    obj.setColType("decimal(5,3)");
    data = new ColumnStatisticsData();
    DecimalColumnStatsData decData = new DecimalColumnStatsData();
    LOG.debug("Setting decimal high value to " + decHigh.getScale() + " <" + new String(decHigh.getUnscaled()) + ">");
    decData.setHighValue(decHigh);
    decData.setLowValue(decLow);
    decData.setNumNulls(decNulls);
    decData.setNumDVs(decDVs);
    data.setDecimalStats(decData);
    obj.setStatsData(data);
    stats.addToStatsObj(obj);
    store.updateTableColumnStatistics(stats);
    stats = store.getTableColumnStatistics(dbname, tableName, Arrays.asList(boolcol, longcol, doublecol, stringcol, binarycol, decimalcol));
    Assert.assertEquals(now, stats.getStatsDesc().getLastAnalyzed());
    Assert.assertEquals(dbname, stats.getStatsDesc().getDbName());
    Assert.assertEquals(tableName, stats.getStatsDesc().getTableName());
    Assert.assertTrue(stats.getStatsDesc().isIsTblLevel());
    Assert.assertEquals(6, stats.getStatsObjSize());
    ColumnStatisticsData colData = stats.getStatsObj().get(0).getStatsData();
    Assert.assertEquals(ColumnStatisticsData._Fields.BOOLEAN_STATS, colData.getSetField());
    boolData = colData.getBooleanStats();
    Assert.assertEquals(trues, boolData.getNumTrues());
    Assert.assertEquals(falses, boolData.getNumFalses());
    Assert.assertEquals(booleanNulls, boolData.getNumNulls());
    colData = stats.getStatsObj().get(1).getStatsData();
    Assert.assertEquals(ColumnStatisticsData._Fields.LONG_STATS, colData.getSetField());
    longData = colData.getLongStats();
    Assert.assertEquals(longHigh, longData.getHighValue());
    Assert.assertEquals(longLow, longData.getLowValue());
    Assert.assertEquals(longNulls, longData.getNumNulls());
    Assert.assertEquals(longDVs, longData.getNumDVs());
    colData = stats.getStatsObj().get(2).getStatsData();
    Assert.assertEquals(ColumnStatisticsData._Fields.DOUBLE_STATS, colData.getSetField());
    doubleData = colData.getDoubleStats();
    Assert.assertEquals(doubleHigh, doubleData.getHighValue(), 0.01);
    Assert.assertEquals(doubleLow, doubleData.getLowValue(), 0.01);
    Assert.assertEquals(doubleNulls, doubleData.getNumNulls());
    Assert.assertEquals(doubleDVs, doubleData.getNumDVs());
    colData = stats.getStatsObj().get(3).getStatsData();
    Assert.assertEquals(ColumnStatisticsData._Fields.STRING_STATS, colData.getSetField());
    strData = colData.getStringStats();
    Assert.assertEquals(strMaxLen, strData.getMaxColLen());
    Assert.assertEquals(strAvgLen, strData.getAvgColLen(), 0.01);
    Assert.assertEquals(strNulls, strData.getNumNulls());
    Assert.assertEquals(strDVs, strData.getNumDVs());
    colData = stats.getStatsObj().get(4).getStatsData();
    Assert.assertEquals(ColumnStatisticsData._Fields.BINARY_STATS, colData.getSetField());
    binData = colData.getBinaryStats();
    Assert.assertEquals(binMaxLen, binData.getMaxColLen());
    Assert.assertEquals(binAvgLen, binData.getAvgColLen(), 0.01);
    Assert.assertEquals(binNulls, binData.getNumNulls());
    colData = stats.getStatsObj().get(5).getStatsData();
    Assert.assertEquals(ColumnStatisticsData._Fields.DECIMAL_STATS, colData.getSetField());
    decData = colData.getDecimalStats();
    Assert.assertEquals(decHigh, decData.getHighValue());
    Assert.assertEquals(decLow, decData.getLowValue());
    Assert.assertEquals(decNulls, decData.getNumNulls());
    Assert.assertEquals(decDVs, decData.getNumDVs());
}

Example 17 with DecimalColumnStatsData

use of org.apache.hadoop.hive.metastore.api.DecimalColumnStatsData in project hive by apache.

the class TestHBaseAggregateStatsNDVUniformDist method TwoEndsAndMiddleOfPartitionsHaveBitVectorStatusDecimal.

@Test
public void TwoEndsAndMiddleOfPartitionsHaveBitVectorStatusDecimal() throws Exception {
    String dbName = "default";
    String tableName = "snp";
    long now = System.currentTimeMillis();
    List<FieldSchema> cols = new ArrayList<>();
    cols.add(new FieldSchema("col5_decimal", "decimal", "nocomment"));
    SerDeInfo serde = new SerDeInfo("serde", "seriallib", null);
    StorageDescriptor sd = new StorageDescriptor(cols, "file:/tmp", "input", "output", false, 0, serde, null, null, Collections.<String, String>emptyMap());
    List<FieldSchema> partCols = new ArrayList<>();
    partCols.add(new FieldSchema("ds", "string", ""));
    Table table = new Table(tableName, dbName, "me", (int) now, (int) now, 0, sd, partCols, Collections.<String, String>emptyMap(), null, null, null);
    store.createTable(table);
    List<List<String>> partVals = new ArrayList<>();
    for (int i = 0; i < 10; i++) {
        List<String> partVal = Arrays.asList("" + i);
        partVals.add(partVal);
        StorageDescriptor psd = new StorageDescriptor(sd);
        psd.setLocation("file:/tmp/default/hit/ds=" + partVal);
        Partition part = new Partition(partVal, dbName, tableName, (int) now, (int) now, psd, Collections.<String, String>emptyMap());
        store.addPartition(part);
        if (i == 0 || i == 2 || i == 3 || i == 5 || i == 6 || i == 8) {
            ColumnStatistics cs = new ColumnStatistics();
            ColumnStatisticsDesc desc = new ColumnStatisticsDesc(false, dbName, tableName);
            desc.setLastAnalyzed(now);
            desc.setPartName("ds=" + partVal);
            cs.setStatsDesc(desc);
            ColumnStatisticsObj obj = new ColumnStatisticsObj();
            obj.setColName("col5_decimal");
            obj.setColType("decimal");
            ColumnStatisticsData data = new ColumnStatisticsData();
            DecimalColumnStatsData dcsd = new DecimalColumnStatsData();
            dcsd.setHighValue(StatObjectConverter.createThriftDecimal("" + (1000 + i)));
            dcsd.setLowValue(StatObjectConverter.createThriftDecimal("" + (-1000 - i)));
            dcsd.setNumNulls(i);
            dcsd.setNumDVs(10 * i + 1);
            dcsd.setBitVectors(bitVectors[i / 5]);
            data.setDecimalStats(dcsd);
            obj.setStatsData(data);
            cs.addToStatsObj(obj);
            store.updatePartitionColumnStatistics(cs, partVal);
        }
    }
    Checker statChecker = new Checker() {

        @Override
        public void checkStats(AggrStats aggrStats) throws Exception {
            Assert.assertEquals(6, aggrStats.getPartsFound());
            Assert.assertEquals(1, aggrStats.getColStatsSize());
            ColumnStatisticsObj cso = aggrStats.getColStats().get(0);
            Assert.assertEquals("col5_decimal", cso.getColName());
            Assert.assertEquals("decimal", cso.getColType());
            DecimalColumnStatsData lcsd = cso.getStatsData().getDecimalStats();
            Assert.assertEquals(1010, HBaseUtils.getDoubleValue(lcsd.getHighValue()), 0.01);
            Assert.assertEquals(-1010, HBaseUtils.getDoubleValue(lcsd.getLowValue()), 0.01);
            Assert.assertEquals(40, lcsd.getNumNulls());
            Assert.assertEquals(12, lcsd.getNumDVs());
        }
    };
    List<String> partNames = new ArrayList<>();
    for (int i = 0; i < 10; i++) {
        partNames.add("ds=" + i);
    }
    AggrStats aggrStats = store.get_aggr_stats_for(dbName, tableName, partNames, Arrays.asList("col5_decimal"));
    statChecker.checkStats(aggrStats);
}

Example 18 with DecimalColumnStatsData

use of org.apache.hadoop.hive.metastore.api.DecimalColumnStatsData in project hive by apache.

the class HBaseUtils method statsForOneColumnFromProtoBuf.

private static ColumnStatisticsObj statsForOneColumnFromProtoBuf(ColumnStatistics partitionColumnStats, HbaseMetastoreProto.ColumnStats proto) throws IOException {
    ColumnStatisticsObj colStats = new ColumnStatisticsObj();
    long lastAnalyzed = proto.getLastAnalyzed();
    if (partitionColumnStats != null) {
        partitionColumnStats.getStatsDesc().setLastAnalyzed(Math.max(lastAnalyzed, partitionColumnStats.getStatsDesc().getLastAnalyzed()));
    }
    colStats.setColType(proto.getColumnType());
    colStats.setColName(proto.getColumnName());
    ColumnStatisticsData colData = new ColumnStatisticsData();
    if (proto.hasBoolStats()) {
        BooleanColumnStatsData boolData = new BooleanColumnStatsData();
        boolData.setNumTrues(proto.getBoolStats().getNumTrues());
        boolData.setNumFalses(proto.getBoolStats().getNumFalses());
        boolData.setNumNulls(proto.getNumNulls());
        colData.setBooleanStats(boolData);
    } else if (proto.hasLongStats()) {
        LongColumnStatsData longData = new LongColumnStatsData();
        if (proto.getLongStats().hasLowValue()) {
            longData.setLowValue(proto.getLongStats().getLowValue());
        }
        if (proto.getLongStats().hasHighValue()) {
            longData.setHighValue(proto.getLongStats().getHighValue());
        }
        longData.setNumNulls(proto.getNumNulls());
        longData.setNumDVs(proto.getNumDistinctValues());
        longData.setBitVectors(proto.getBitVectors());
        colData.setLongStats(longData);
    } else if (proto.hasDoubleStats()) {
        DoubleColumnStatsData doubleData = new DoubleColumnStatsData();
        if (proto.getDoubleStats().hasLowValue()) {
            doubleData.setLowValue(proto.getDoubleStats().getLowValue());
        }
        if (proto.getDoubleStats().hasHighValue()) {
            doubleData.setHighValue(proto.getDoubleStats().getHighValue());
        }
        doubleData.setNumNulls(proto.getNumNulls());
        doubleData.setNumDVs(proto.getNumDistinctValues());
        doubleData.setBitVectors(proto.getBitVectors());
        colData.setDoubleStats(doubleData);
    } else if (proto.hasStringStats()) {
        StringColumnStatsData stringData = new StringColumnStatsData();
        stringData.setMaxColLen(proto.getStringStats().getMaxColLength());
        stringData.setAvgColLen(proto.getStringStats().getAvgColLength());
        stringData.setNumNulls(proto.getNumNulls());
        stringData.setNumDVs(proto.getNumDistinctValues());
        stringData.setBitVectors(proto.getBitVectors());
        colData.setStringStats(stringData);
    } else if (proto.hasBinaryStats()) {
        BinaryColumnStatsData binaryData = new BinaryColumnStatsData();
        binaryData.setMaxColLen(proto.getBinaryStats().getMaxColLength());
        binaryData.setAvgColLen(proto.getBinaryStats().getAvgColLength());
        binaryData.setNumNulls(proto.getNumNulls());
        colData.setBinaryStats(binaryData);
    } else if (proto.hasDecimalStats()) {
        DecimalColumnStatsData decimalData = new DecimalColumnStatsData();
        if (proto.getDecimalStats().hasHighValue()) {
            Decimal hiVal = new Decimal();
            hiVal.setUnscaled(proto.getDecimalStats().getHighValue().getUnscaled().toByteArray());
            hiVal.setScale((short) proto.getDecimalStats().getHighValue().getScale());
            decimalData.setHighValue(hiVal);
        }
        if (proto.getDecimalStats().hasLowValue()) {
            Decimal loVal = new Decimal();
            loVal.setUnscaled(proto.getDecimalStats().getLowValue().getUnscaled().toByteArray());
            loVal.setScale((short) proto.getDecimalStats().getLowValue().getScale());
            decimalData.setLowValue(loVal);
        }
        decimalData.setNumNulls(proto.getNumNulls());
        decimalData.setNumDVs(proto.getNumDistinctValues());
        decimalData.setBitVectors(proto.getBitVectors());
        colData.setDecimalStats(decimalData);
    } else {
        throw new RuntimeException("Woh, bad.  Unknown stats type!");
    }
    colStats.setStatsData(colData);
    return colStats;
}

Example 19 with DecimalColumnStatsData

use of org.apache.hadoop.hive.metastore.api.DecimalColumnStatsData in project hive by apache.

the class HBaseUtils method protoBufStatsForOneColumn.

private static HbaseMetastoreProto.ColumnStats protoBufStatsForOneColumn(ColumnStatistics partitionColumnStats, ColumnStatisticsObj colStats) throws IOException {
    HbaseMetastoreProto.ColumnStats.Builder builder = HbaseMetastoreProto.ColumnStats.newBuilder();
    if (partitionColumnStats != null) {
        builder.setLastAnalyzed(partitionColumnStats.getStatsDesc().getLastAnalyzed());
    }
    assert colStats.getColType() != null;
    builder.setColumnType(colStats.getColType());
    assert colStats.getColName() != null;
    builder.setColumnName(colStats.getColName());
    ColumnStatisticsData colData = colStats.getStatsData();
    switch(colData.getSetField()) {
        case BOOLEAN_STATS:
            BooleanColumnStatsData boolData = colData.getBooleanStats();
            builder.setNumNulls(boolData.getNumNulls());
            builder.setBoolStats(HbaseMetastoreProto.ColumnStats.BooleanStats.newBuilder().setNumTrues(boolData.getNumTrues()).setNumFalses(boolData.getNumFalses()).build());
            break;
        case LONG_STATS:
            LongColumnStatsData longData = colData.getLongStats();
            builder.setNumNulls(longData.getNumNulls());
            builder.setNumDistinctValues(longData.getNumDVs());
            if (longData.isSetBitVectors()) {
                builder.setBitVectors(longData.getBitVectors());
            }
            builder.setLongStats(HbaseMetastoreProto.ColumnStats.LongStats.newBuilder().setLowValue(longData.getLowValue()).setHighValue(longData.getHighValue()).build());
            break;
        case DOUBLE_STATS:
            DoubleColumnStatsData doubleData = colData.getDoubleStats();
            builder.setNumNulls(doubleData.getNumNulls());
            builder.setNumDistinctValues(doubleData.getNumDVs());
            if (doubleData.isSetBitVectors()) {
                builder.setBitVectors(doubleData.getBitVectors());
            }
            builder.setDoubleStats(HbaseMetastoreProto.ColumnStats.DoubleStats.newBuilder().setLowValue(doubleData.getLowValue()).setHighValue(doubleData.getHighValue()).build());
            break;
        case STRING_STATS:
            StringColumnStatsData stringData = colData.getStringStats();
            builder.setNumNulls(stringData.getNumNulls());
            builder.setNumDistinctValues(stringData.getNumDVs());
            if (stringData.isSetBitVectors()) {
                builder.setBitVectors(stringData.getBitVectors());
            }
            builder.setStringStats(HbaseMetastoreProto.ColumnStats.StringStats.newBuilder().setMaxColLength(stringData.getMaxColLen()).setAvgColLength(stringData.getAvgColLen()).build());
            break;
        case BINARY_STATS:
            BinaryColumnStatsData binaryData = colData.getBinaryStats();
            builder.setNumNulls(binaryData.getNumNulls());
            builder.setBinaryStats(HbaseMetastoreProto.ColumnStats.StringStats.newBuilder().setMaxColLength(binaryData.getMaxColLen()).setAvgColLength(binaryData.getAvgColLen()).build());
            break;
        case DECIMAL_STATS:
            DecimalColumnStatsData decimalData = colData.getDecimalStats();
            builder.setNumNulls(decimalData.getNumNulls());
            builder.setNumDistinctValues(decimalData.getNumDVs());
            if (decimalData.isSetBitVectors()) {
                builder.setBitVectors(decimalData.getBitVectors());
            }
            if (decimalData.getLowValue() != null && decimalData.getHighValue() != null) {
                builder.setDecimalStats(HbaseMetastoreProto.ColumnStats.DecimalStats.newBuilder().setLowValue(HbaseMetastoreProto.ColumnStats.DecimalStats.Decimal.newBuilder().setUnscaled(ByteString.copyFrom(decimalData.getLowValue().getUnscaled())).setScale(decimalData.getLowValue().getScale()).build()).setHighValue(HbaseMetastoreProto.ColumnStats.DecimalStats.Decimal.newBuilder().setUnscaled(ByteString.copyFrom(decimalData.getHighValue().getUnscaled())).setScale(decimalData.getHighValue().getScale()).build())).build();
            } else {
                builder.setDecimalStats(HbaseMetastoreProto.ColumnStats.DecimalStats.newBuilder().clear().build());
            }
            break;
        default:
            throw new RuntimeException("Woh, bad.  Unknown stats type!");
    }
    return builder.build();
}

Example 20 with DecimalColumnStatsData

use of org.apache.hadoop.hive.metastore.api.DecimalColumnStatsData in project hive by apache.

the class DecimalColumnStatsAggregator method aggregate.

@Override
public ColumnStatisticsObj aggregate(String colName, List<String> partNames, List<ColumnStatistics> css) throws MetaException {
    ColumnStatisticsObj statsObj = null;
    // check if all the ColumnStatisticsObjs contain stats and all the ndv are
    // bitvectors
    boolean doAllPartitionContainStats = partNames.size() == css.size();
    boolean isNDVBitVectorSet = true;
    String colType = null;
    for (ColumnStatistics cs : css) {
        if (cs.getStatsObjSize() != 1) {
            throw new MetaException("The number of columns should be exactly one in aggrStats, but found " + cs.getStatsObjSize());
        }
        ColumnStatisticsObj cso = cs.getStatsObjIterator().next();
        if (statsObj == null) {
            colType = cso.getColType();
            statsObj = ColumnStatsAggregatorFactory.newColumnStaticsObj(colName, colType, cso.getStatsData().getSetField());
        }
        if (numBitVectors <= 0 || !cso.getStatsData().getDecimalStats().isSetBitVectors() || cso.getStatsData().getDecimalStats().getBitVectors().length() == 0) {
            isNDVBitVectorSet = false;
            break;
        }
    }
    ColumnStatisticsData columnStatisticsData = new ColumnStatisticsData();
    if (doAllPartitionContainStats || css.size() < 2) {
        DecimalColumnStatsData aggregateData = null;
        long lowerBound = 0;
        long higherBound = 0;
        double densityAvgSum = 0.0;
        NumDistinctValueEstimator ndvEstimator = null;
        if (isNDVBitVectorSet) {
            ndvEstimator = new NumDistinctValueEstimator(numBitVectors);
        }
        for (ColumnStatistics cs : css) {
            ColumnStatisticsObj cso = cs.getStatsObjIterator().next();
            DecimalColumnStatsData newData = cso.getStatsData().getDecimalStats();
            if (useDensityFunctionForNDVEstimation) {
                lowerBound = Math.max(lowerBound, newData.getNumDVs());
                higherBound += newData.getNumDVs();
                densityAvgSum += (HBaseUtils.getDoubleValue(newData.getHighValue()) - HBaseUtils.getDoubleValue(newData.getLowValue())) / newData.getNumDVs();
            }
            if (isNDVBitVectorSet) {
                ndvEstimator.mergeEstimators(new NumDistinctValueEstimator(newData.getBitVectors(), ndvEstimator.getnumBitVectors()));
            }
            if (aggregateData == null) {
                aggregateData = newData.deepCopy();
            } else {
                if (HBaseUtils.getDoubleValue(aggregateData.getLowValue()) < HBaseUtils.getDoubleValue(newData.getLowValue())) {
                    aggregateData.setLowValue(aggregateData.getLowValue());
                } else {
                    aggregateData.setLowValue(newData.getLowValue());
                }
                if (HBaseUtils.getDoubleValue(aggregateData.getHighValue()) > HBaseUtils.getDoubleValue(newData.getHighValue())) {
                    aggregateData.setHighValue(aggregateData.getHighValue());
                } else {
                    aggregateData.setHighValue(newData.getHighValue());
                }
                aggregateData.setNumNulls(aggregateData.getNumNulls() + newData.getNumNulls());
                aggregateData.setNumDVs(Math.max(aggregateData.getNumDVs(), newData.getNumDVs()));
            }
        }
        if (isNDVBitVectorSet) {
            // 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 {
            if (useDensityFunctionForNDVEstimation) {
                // We have estimation, lowerbound and higherbound. We use estimation
                // if it is between lowerbound and higherbound.
                double densityAvg = densityAvgSum / partNames.size();
                long estimation = (long) ((HBaseUtils.getDoubleValue(aggregateData.getHighValue()) - HBaseUtils.getDoubleValue(aggregateData.getLowValue())) / densityAvg);
                if (estimation < lowerBound) {
                    aggregateData.setNumDVs(lowerBound);
                } else if (estimation > higherBound) {
                    aggregateData.setNumDVs(higherBound);
                } else {
                    aggregateData.setNumDVs(estimation);
                }
            } else {
            // Without useDensityFunctionForNDVEstimation, we just use the
            // default one, which is the max of all the partitions and it is
            // already done.
            }
        }
        columnStatisticsData.setDecimalStats(aggregateData);
    } else {
        // we need extrapolation
        Map<String, Integer> indexMap = new HashMap<String, Integer>();
        for (int index = 0; index < partNames.size(); index++) {
            indexMap.put(partNames.get(index), index);
        }
        Map<String, Double> adjustedIndexMap = new HashMap<String, Double>();
        Map<String, ColumnStatisticsData> adjustedStatsMap = new HashMap<String, ColumnStatisticsData>();
        // while we scan the css, we also get the densityAvg, lowerbound and
        // higerbound when useDensityFunctionForNDVEstimation is true.
        double densityAvgSum = 0.0;
        if (!isNDVBitVectorSet) {
            // the traditional extrapolation methods.
            for (ColumnStatistics cs : css) {
                String partName = cs.getStatsDesc().getPartName();
                ColumnStatisticsObj cso = cs.getStatsObjIterator().next();
                DecimalColumnStatsData newData = cso.getStatsData().getDecimalStats();
                if (useDensityFunctionForNDVEstimation) {
                    densityAvgSum += (HBaseUtils.getDoubleValue(newData.getHighValue()) - HBaseUtils.getDoubleValue(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.
            NumDistinctValueEstimator ndvEstimator = new NumDistinctValueEstimator(numBitVectors);
            StringBuilder pseudoPartName = new StringBuilder();
            double pseudoIndexSum = 0;
            int length = 0;
            int curIndex = -1;
            DecimalColumnStatsData aggregateData = null;
            for (ColumnStatistics cs : css) {
                String partName = cs.getStatsDesc().getPartName();
                ColumnStatisticsObj cso = cs.getStatsObjIterator().next();
                DecimalColumnStatsData newData = cso.getStatsData().getDecimalStats();
                // 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 += (HBaseUtils.getDoubleValue(aggregateData.getHighValue()) - HBaseUtils.getDoubleValue(aggregateData.getLowValue())) / aggregateData.getNumDVs();
                        }
                        // reset everything
                        pseudoPartName = new StringBuilder();
                        pseudoIndexSum = 0;
                        length = 0;
                    }
                    aggregateData = null;
                }
                curIndex = indexMap.get(partName);
                pseudoPartName.append(partName);
                pseudoIndexSum += curIndex;
                length++;
                curIndex++;
                if (aggregateData == null) {
                    aggregateData = newData.deepCopy();
                } else {
                    if (HBaseUtils.getDoubleValue(aggregateData.getLowValue()) < HBaseUtils.getDoubleValue(newData.getLowValue())) {
                        aggregateData.setLowValue(aggregateData.getLowValue());
                    } else {
                        aggregateData.setLowValue(newData.getLowValue());
                    }
                    if (HBaseUtils.getDoubleValue(aggregateData.getHighValue()) > HBaseUtils.getDoubleValue(newData.getHighValue())) {
                        aggregateData.setHighValue(aggregateData.getHighValue());
                    } else {
                        aggregateData.setHighValue(newData.getHighValue());
                    }
                    aggregateData.setNumNulls(aggregateData.getNumNulls() + newData.getNumNulls());
                }
                ndvEstimator.mergeEstimators(new NumDistinctValueEstimator(newData.getBitVectors(), ndvEstimator.getnumBitVectors()));
            }
            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 += (HBaseUtils.getDoubleValue(aggregateData.getHighValue()) - HBaseUtils.getDoubleValue(aggregateData.getLowValue())) / aggregateData.getNumDVs();
                }
            }
        }
        extrapolate(columnStatisticsData, partNames.size(), css.size(), adjustedIndexMap, adjustedStatsMap, densityAvgSum / adjustedStatsMap.size());
    }
    statsObj.setStatsData(columnStatisticsData);
    return statsObj;
}