amogh-jahagirdar commented on code in PR #13391: URL: https://github.com/apache/iceberg/pull/13391#discussion_r2220373615
########## arrow/src/main/java/org/apache/iceberg/arrow/vectorized/parquet/VectorizedDeltaEncodedValuesReader.java: ########## @@ -0,0 +1,276 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * 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 + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.iceberg.arrow.vectorized.parquet; + +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.Arrays; +import org.apache.arrow.vector.FieldVector; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.parquet.bytes.ByteBufferInputStream; +import org.apache.parquet.bytes.BytesUtils; +import org.apache.parquet.column.values.ValuesReader; +import org.apache.parquet.column.values.bitpacking.BytePackerForLong; +import org.apache.parquet.column.values.bitpacking.Packer; +import org.apache.parquet.io.ParquetDecodingException; +import org.apache.parquet.io.api.Binary; + +/** + * A {@link VectorizedValuesReader} implementation for the encoding type DELTA_BINARY_PACKED. This + * is adapted from Spark's VectorizedDeltaBinaryPackedReader. + * + * @see <a + * href="https://github.com/apache/parquet-format/blob/master/Encodings.md#delta-encoding-delta_binary_packed--5";> + * Parquet format encodings: DELTA_BINARY_PACKED</a> + */ +public class VectorizedDeltaEncodedValuesReader extends ValuesReader + implements VectorizedValuesReader { + + // header data + private int blockSizeInValues; + private int miniBlocksPerBlock; + private int totalValueCount; + private long firstValue; + + private int miniBlockSizeInValues; + + // values read by the caller + private int valuesRead = 0; + + // variables to keep state of the current block and miniblock + private long lastValueRead; // needed to compute the next value + private long minDeltaInCurrentBlock; // needed to compute the next value + // currentMiniBlock keeps track of the mini block within the current block that + // we read and decoded most recently. Only used as an index into + // bitWidths array + private int currentMiniBlock = 0; + private int[] bitWidths; // bit widths for each miniBlock in the current block + private int remainingInBlock = 0; // values in current block still to be read + private int remainingInMiniBlock = 0; // values in current mini block still to be read + private long[] unpackedValuesBuffer; + + private ByteBufferInputStream inputStream; + + // temporary buffers used by readInteger and readLong + private int intVal; + private long longVal; + + @Override + public void initFromPage(int valueCount, ByteBufferInputStream in) throws IOException { + Preconditions.checkArgument( + valueCount >= 1, "Page must have at least one value, but it has " + valueCount); + this.inputStream = in; + // Read the header + this.blockSizeInValues = BytesUtils.readUnsignedVarInt(this.inputStream); + this.miniBlocksPerBlock = BytesUtils.readUnsignedVarInt(this.inputStream); + double miniSize = (double) blockSizeInValues / miniBlocksPerBlock; + Preconditions.checkArgument( + miniSize % 8 == 0, "miniBlockSize must be multiple of 8, but it's " + miniSize); + this.miniBlockSizeInValues = (int) miniSize; + // True value count. May be less than valueCount because of nulls + this.totalValueCount = BytesUtils.readUnsignedVarInt(this.inputStream); + this.bitWidths = new int[miniBlocksPerBlock]; + this.unpackedValuesBuffer = new long[miniBlockSizeInValues]; + // read the first value + firstValue = BytesUtils.readZigZagVarLong(this.inputStream); + } + + @Override + public byte readByte() { + throw new UnsupportedOperationException("readByte is not supported"); + } + + @Override + public short readShort() { + throw new UnsupportedOperationException("readShort is not supported"); + } + + @Override + public int readInteger() { + readValues(1, null, 0, INT_SIZE, (f, i, v) -> intVal = (int) v); + return intVal; + } + + @Override + public long readLong() { + readValues(1, null, 0, LONG_SIZE, (f, i, v) -> longVal = v); + return longVal; + } + + @Override + public void skip() { + throw new UnsupportedOperationException("skip is not supported"); + } + + @Override + public Binary readBinary(int len) { + throw new UnsupportedOperationException("readBinary is not supported"); + } + + @Override + public void readIntegers(int total, FieldVector vec, int rowId) { + readValues(total, vec, rowId, INT_SIZE, (f, i, v) -> f.getDataBuffer().setLong(i, v)); + } + + @Override + public void readLongs(int total, FieldVector vec, int rowId) { + readValues(total, vec, rowId, LONG_SIZE, (f, i, v) -> f.getDataBuffer().setLong(i, v)); + } + + @Override + public void readFloats(int total, FieldVector vec, int rowId) { + throw new UnsupportedOperationException("readFloats is not supported"); + } + + @Override + public void readDoubles(int total, FieldVector vec, int rowId) { + throw new UnsupportedOperationException("readDoubles is not supported"); + } + + private void readValues( + int total, FieldVector vec, int rowId, int typeWidth, IntegerOutputWriter outputWriter) { + if (valuesRead + total > totalValueCount) { + throw new ParquetDecodingException( + "No more values to read. Total values read: " + + valuesRead + + ", total count: " + + totalValueCount + + ", trying to read " + + total + + " more."); + } + int remaining = total; + int currentRowId = rowId; + // First value + if (valuesRead == 0) { + outputWriter.write(vec, ((long) (currentRowId + valuesRead) * typeWidth), firstValue); + lastValueRead = firstValue; + currentRowId++; + remaining--; + } + + while (remaining > 0) { + int loadedRows; + try { + loadedRows = loadMiniBlockToOutput(remaining, vec, currentRowId, typeWidth, outputWriter); + } catch (IOException e) { + throw new ParquetDecodingException("Error reading mini block.", e); + } + currentRowId += loadedRows; + remaining -= loadedRows; + } + valuesRead = total - remaining; + } + + /** + * Read from a mini block. Read at most 'remaining' values into output. + * + * @return the number of values read into output + */ + private int loadMiniBlockToOutput( + int remaining, FieldVector vec, int rowId, int typeWidth, IntegerOutputWriter outputWriter) + throws IOException { + + // new block; read the block header + if (remainingInBlock == 0) { + readBlockHeader(); + } + + // new miniblock, unpack the miniblock + if (remainingInMiniBlock == 0) { + unpackMiniBlock(); + } + + // read values from miniblock + int valuesReadInMiniBlock = 0; + for (int i = miniBlockSizeInValues - remainingInMiniBlock; + i < miniBlockSizeInValues && valuesReadInMiniBlock < remaining; + i++) { + // calculate values from deltas unpacked for current block + long outValue = lastValueRead + minDeltaInCurrentBlock + unpackedValuesBuffer[i]; + lastValueRead = outValue; + outputWriter.write(vec, ((long) (rowId + valuesReadInMiniBlock) * typeWidth), outValue); + remainingInBlock--; + remainingInMiniBlock--; + valuesReadInMiniBlock++; + } + + return valuesReadInMiniBlock; + } + + private void readBlockHeader() { + try { + minDeltaInCurrentBlock = BytesUtils.readZigZagVarLong(inputStream); + } catch (IOException e) { + throw new ParquetDecodingException("Can not read min delta in current block", e); + } + readBitWidthsForMiniBlocks(); + remainingInBlock = blockSizeInValues; + currentMiniBlock = 0; + remainingInMiniBlock = 0; + } + + /** + * mini block has a size of 8*n, unpack 32 value each time + * + * <p>see org.apache.parquet.column.values.delta.DeltaBinaryPackingValuesReader#unpackMiniBlock + */ + private void unpackMiniBlock() throws IOException { + Arrays.fill(this.unpackedValuesBuffer, 0); + BytePackerForLong packer = + Packer.LITTLE_ENDIAN.newBytePackerForLong(bitWidths[currentMiniBlock]); + for (int j = 0; j < miniBlockSizeInValues; j += 8) { + ByteBuffer buffer = inputStream.slice(packer.getBitWidth()); + if (buffer.hasArray()) { + packer.unpack8Values( + buffer.array(), buffer.arrayOffset() + buffer.position(), unpackedValuesBuffer, j); + } else { + packer.unpack8Values(buffer, buffer.position(), unpackedValuesBuffer, j); Review Comment: actually sorry that I missed this, but I was testing here and do we need the actual `buffer.hasArray()` condition? Unpacking the mini block into the buffer should always work no? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
