Phoenix创建索引源码过程

date: 2020-09-27 13:50:00

updated: 2020-09-28 16:30:00

Phoenix创建索引源码过程

org.apache.phoenix.index.IndexMaintainer

public byte[] buildRowKey(ValueGetter valueGetter, ImmutableBytesWritable rowKeyPtr, byte[] regionStartKey, byte[] regionEndKey, long ts)  {

    ImmutableBytesWritable ptr = new ImmutableBytesWritable();

//判断是否是构建本地索引，考虑两个条件：1.本地索引是否开启 2.startRK 是否传进来了

    boolean prependRegionStartKey = isLocalIndex && regionStartKey != null;

    boolean isIndexSalted = !isLocalIndex && nIndexSaltBuckets > 0;

//如果开启本地索引，则在数据前面添加前缀，判断startRK是否是region起始startRK，如果是则使用该region的EndRK

    int prefixKeyLength =

            prependRegionStartKey ? (regionStartKey.length != 0 ? regionStartKey.length

                    : regionEndKey.length) : 0;

    TrustedByteArrayOutputStream stream = new TrustedByteArrayOutputStream(estimatedIndexRowKeyBytes + (prependRegionStartKey ? prefixKeyLength : 0));

// 构建数据流对象，对数据进行put

    DataOutput output = new DataOutputStream(stream);

如果是本地索引，则在rowkey前加入startrowkey索引

// For local indexes, we must prepend the row key with the start region key

if (prependRegionStartKey) {

    if (regionStartKey.length == 0) {

        // 如果startRK为null，则其实使用的endRK

        output.write(new byte[prefixKeyLength]);

    } else {

        output.write(regionStartKey);

    }

}

判断是否有加盐，如果有，则增加一个标志位，后面再更改这个标志位

if (isIndexSalted) {

    output.write(0); // will be set at end to index salt byte

}

如果在索引视图id不为null，会在索引rowkey中加入视图id

if (viewIndexId != null) {

    output.write(viewIndexId);

}

dataRowKeySchema是数据表的信息，忽略在视图变量的中常量值，并标记出原表pk的rowkey的offset 和 length，方便后面定位数据表rowkey插入。

for (int i = dataPosOffset; i < dataRowKeySchema.getFieldCount(); i++) {

    Boolean hasValue=dataRowKeySchema.next(ptr, i, maxRowKeyOffset);

    // Ignore view constants from the data table, as these

    // don't need to appear in the index (as they're the

    // same for all rows in this index)

    if (!viewConstantColumnBitSet.get(i)) {

        int pos = rowKeyMetaData.getIndexPkPosition(i-dataPosOffset);

        if (Boolean.TRUE.equals(hasValue)) {

            dataRowKeyLocator[0][pos] = ptr.getOffset();

            dataRowKeyLocator[1][pos] = ptr.getLength();

        } else {

            dataRowKeyLocator[0][pos] = 0;

            dataRowKeyLocator[1][pos] = 0;

        }

    }

}

考虑索引的数据的顺序

// 获取表达式索引，表达式索引默认值都为1，未开启的时候isNullAble为true

Iterator<Expression> expressionIterator = indexedExpressions.iterator();

//  nIndexedColumns 的构成是索引列+主键 如果是组合索引，则循环多个索引列

for (int i = 0; i < nIndexedColumns; i++) {

    PDataType dataColumnType;

    boolean isNullable;

    SortOrder dataSortOrder;

// dataPkPosition为-1则表示为表达式索引，否则为属性索引

    if (dataPkPosition[i] == EXPRESSION_NOT_PRESENT) {

       Expression expression = expressionIterator.next();

       dataColumnType = expression.getDataType();

       dataSortOrder = expression.getSortOrder();

        isNullable = expression.isNullable();

       expression.evaluate(new ValueGetterTuple(valueGetter, ts), ptr);

    }

//  主键pk 走这个分支

    else {

        Field field = dataRowKeySchema.getField(dataPkPosition[i]);

        dataColumnType = field.getDataType();

        ptr.set(rowKeyPtr.get(), dataRowKeyLocator[0][i], dataRowKeyLocator[1][i]);

        dataSortOrder = field.getSortOrder();

        isNullable = field.isNullable();

    }

// 考虑列值的顺序，考虑字节的比较，考虑索引列的顺序

// 判断查询是否desc，默认为asc。

    boolean isDataColumnInverted = dataSortOrder != SortOrder.ASC;

// 获取索引列的的数据类型，详情看后面getIndexColumnDataType函数

    PDataType indexColumnType = IndexUtil.getIndexColumnDataType(isNullable, dataColumnType);

//根据数据列返回不同的datatype，判断该列是否可比较。不可比较的列有decimal，varchar，boolean，Binary

    boolean isBytesComparable = dataColumnType.isBytesComparableWith(indexColumnType);

// 获取列是否是逆序的

    boolean isIndexColumnDesc = descIndexColumnBitSet.get(i);

    if (isBytesComparable && isDataColumnInverted == isIndexColumnDesc) {

        output.write(ptr.get(), ptr.getOffset(), ptr.getLength());

    } else {

        if (!isBytesComparable)  {

// 让不可比较的类型具有可比性

            indexColumnType.coerceBytes(ptr, dataColumnType, dataSortOrder, SortOrder.getDefault());

        }

// 按位取异或值，二进制数比较肯定是字典序，从最高位开始比较，直到遇到第一个不一样的位，这个位上哪个数等于1哪个数就较大。

        if (isDataColumnInverted != isIndexColumnDesc) {

            writeInverted(ptr.get(), ptr.getOffset(), ptr.getLength(), output);

        } else {

            output.write(ptr.get(), ptr.getOffset(), ptr.getLength());

        }

    }

// 判断数据是不是一个固定长度的字段，如果不是根据数据的正序逆序添加一个标志位

    if (!indexColumnType.isFixedWidth()) {

        output.writeByte(SchemaUtil.getSeparatorByte(rowKeyOrderOptimizable, ptr.getLength() == 0, isIndexColumnDesc ? SortOrder.DESC : SortOrder.ASC));

    }

}

填充开始的加盐部分的字节位，规则是根据数据做hash，然后再对nIndexSaltBuckets取余

if (isIndexSalted) {

    // Set salt byte

    byte saltByte = SaltingUtil.getSaltingByte(indexRowKey, SaltingUtil.NUM_SALTING_BYTES, length-SaltingUtil.NUM_SALTING_BYTES, nIndexSaltBuckets);

    indexRowKey[0] = saltByte;

}

返回所有的生成的rowkey

return indexRowKey.length == length ? indexRowKey : Arrays.copyOf(indexRowKey, length);

根据数据列返回不同的datatype，判断该列是否可比较。不可比较的列有decimal，varchar，boolean，Binary等

// Since we cannot have nullable fixed length in a row key

// we need to translate to variable length. The verification that we have a valid index

// row key was already done, so here we just need to convert from one built-in type to

// another.

public static PDataType getIndexColumnDataType(boolean isNullable, PDataType dataType) {

    if (dataType == null || !isNullable || !dataType.isFixedWidth()) {

        return dataType;

    }

    // for fixed length numeric types and boolean

    if (dataType.isCastableTo(PDecimal.INSTANCE)) {

        return PDecimal.INSTANCE;

    }

    // for CHAR

    if (dataType.isCoercibleTo(PVarchar.INSTANCE)) {

        return PVarchar.INSTANCE;

    }

    if (PBinary.INSTANCE.equals(dataType)) {

        return PVarbinary.INSTANCE;

    }

    throw new IllegalArgumentException("Unsupported non nullable type " + dataType);

}

让数据有可比性

protected static int toBytes(BigDecimal v, byte[] result, final int offset, int length) {

    // From scale to exponent byte (if BigDecimal is positive): (-(scale+(scale % 2 == 0 : 0 : 1)) / 2 + 65) | 0x80

    // If scale % 2 is 1 (i.e. it's odd), then multiple last base-100 digit by 10

    // For example: new BigDecimal(BigInteger.valueOf(1), -4);

    // (byte)((-(-4+0) / 2 + 65) | 0x80) = -61

    // From scale to exponent byte (if BigDecimal is negative): ~(-(scale+1)/2 + 65 + 128) & 0x7F

    // For example: new BigDecimal(BigInteger.valueOf(1), 2);

    // ~(-2/2 + 65 + 128) & 0x7F = 63

巴特西

Phoenix创建索引源码过程

Phoenix创建索引源码过程

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