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Example 1 with GenericInternalException

use of com.facebook.presto.common.GenericInternalException in project presto by prestodb.

the class SliceDirectBatchStreamReader method readBlock.

@Override
public Block readBlock() throws IOException {
    if (!rowGroupOpen) {
        openRowGroup();
    }
    if (readOffset > 0) {
        if (presentStream != null) {
            // skip ahead the present bit reader, but count the set bits
            // and use this as the skip size for the length reader
            readOffset = presentStream.countBitsSet(readOffset);
        }
        if (readOffset > 0) {
            if (lengthStream == null) {
                throw new OrcCorruptionException(streamDescriptor.getOrcDataSourceId(), "Value is not null but length stream is not present");
            }
            long dataSkipSize = lengthStream.sum(readOffset);
            if (dataSkipSize > 0) {
                if (dataStream == null) {
                    throw new OrcCorruptionException(streamDescriptor.getOrcDataSourceId(), "Value is not null but data stream is not present");
                }
                dataStream.skip(dataSkipSize);
            }
        }
    }
    if (lengthStream == null) {
        if (presentStream == null) {
            throw new OrcCorruptionException(streamDescriptor.getOrcDataSourceId(), "Value is null but present stream is missing");
        }
        presentStream.skip(nextBatchSize);
        Block nullValueBlock = readAllNullsBlock();
        readOffset = 0;
        nextBatchSize = 0;
        return nullValueBlock;
    }
    // create new isNullVector and offsetVector for VariableWidthBlock
    boolean[] isNullVector = null;
    // We will use the offsetVector as the buffer to read the length values from lengthStream,
    // and the length values will be converted in-place to an offset vector.
    int[] offsetVector = new int[nextBatchSize + 1];
    if (presentStream == null) {
        lengthStream.next(offsetVector, nextBatchSize);
    } else {
        isNullVector = new boolean[nextBatchSize];
        int nullCount = presentStream.getUnsetBits(nextBatchSize, isNullVector);
        if (nullCount == nextBatchSize) {
            // all nulls
            Block nullValueBlock = readAllNullsBlock();
            readOffset = 0;
            nextBatchSize = 0;
            return nullValueBlock;
        }
        if (nullCount == 0) {
            isNullVector = null;
            lengthStream.next(offsetVector, nextBatchSize);
        } else {
            lengthStream.next(offsetVector, nextBatchSize - nullCount);
            unpackLengthNulls(offsetVector, isNullVector, nextBatchSize - nullCount);
        }
    }
    // Calculate the total length for all entries. Note that the values in the offsetVector are still length values now.
    long totalLength = 0;
    for (int i = 0; i < nextBatchSize; i++) {
        totalLength += offsetVector[i];
    }
    int currentBatchSize = nextBatchSize;
    readOffset = 0;
    nextBatchSize = 0;
    if (totalLength == 0) {
        return new VariableWidthBlock(currentBatchSize, EMPTY_SLICE, offsetVector, Optional.ofNullable(isNullVector));
    }
    if (totalLength > ONE_GIGABYTE) {
        throw new GenericInternalException(format("Values in column \"%s\" are too large to process for Presto. %s column values are larger than 1GB [%s]", streamDescriptor.getFieldName(), currentBatchSize, streamDescriptor.getOrcDataSourceId()));
    }
    if (dataStream == null) {
        throw new OrcCorruptionException(streamDescriptor.getOrcDataSourceId(), "Value is not null but data stream is missing");
    }
    // allocate enough space to read
    byte[] data = new byte[toIntExact(totalLength)];
    Slice slice = Slices.wrappedBuffer(data);
    if (maxCodePointCount < 0) {
        // unbounded, simply read all data in on shot
        dataStream.next(data, 0, data.length);
        convertLengthVectorToOffsetVector(offsetVector);
    } else {
        // We do the following operations together in the for loop:
        // * truncate strings
        // * convert original length values in offsetVector into truncated offset values
        int currentLength = offsetVector[0];
        offsetVector[0] = 0;
        for (int i = 1; i <= currentBatchSize; i++) {
            int nextLength = offsetVector[i];
            if (isNullVector != null && isNullVector[i - 1]) {
                checkState(currentLength == 0, "Corruption in slice direct stream: length is non-zero for null entry");
                offsetVector[i] = offsetVector[i - 1];
                currentLength = nextLength;
                continue;
            }
            int offset = offsetVector[i - 1];
            // read data without truncation
            dataStream.next(data, offset, offset + currentLength);
            // adjust offsetVector with truncated length
            int truncatedLength = computeTruncatedLength(slice, offset, currentLength, maxCodePointCount, isCharType);
            verify(truncatedLength >= 0);
            offsetVector[i] = offset + truncatedLength;
            currentLength = nextLength;
        }
    }
    // this can lead to over-retention but unlikely to happen given truncation rarely happens
    return new VariableWidthBlock(currentBatchSize, slice, offsetVector, Optional.ofNullable(isNullVector));
}
Also used : GenericInternalException(com.facebook.presto.common.GenericInternalException) Slice(io.airlift.slice.Slice) RunLengthEncodedBlock(com.facebook.presto.common.block.RunLengthEncodedBlock) VariableWidthBlock(com.facebook.presto.common.block.VariableWidthBlock) Block(com.facebook.presto.common.block.Block) OrcCorruptionException(com.facebook.presto.orc.OrcCorruptionException) VariableWidthBlock(com.facebook.presto.common.block.VariableWidthBlock)

Aggregations

GenericInternalException (com.facebook.presto.common.GenericInternalException)1 Block (com.facebook.presto.common.block.Block)1 RunLengthEncodedBlock (com.facebook.presto.common.block.RunLengthEncodedBlock)1 VariableWidthBlock (com.facebook.presto.common.block.VariableWidthBlock)1 OrcCorruptionException (com.facebook.presto.orc.OrcCorruptionException)1 Slice (io.airlift.slice.Slice)1