deniskuzZ commented on code in PR #6793: URL: https://github.com/apache/hive/pull/6793#discussion_r4155170769
########## llap-server/src/java/org/apache/hadoop/hive/llap/io/decode/ParquetCachedPageReadStore.java: ########## @@ -0,0 +1,341 @@ +/* + * 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.hadoop.hive.llap.io.decode; + +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.ArrayDeque; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.Queue; + +import org.apache.hadoop.hive.common.io.encoded.MemoryBuffer; +import org.apache.hadoop.hive.llap.io.encoded.ParquetEncodedColumnBatch; +import org.apache.parquet.bytes.ByteBufferInputStream; +import org.apache.parquet.bytes.BytesInput; +import org.apache.parquet.column.ColumnDescriptor; +import org.apache.parquet.column.page.DataPage; +import org.apache.parquet.column.page.DataPageV1; +import org.apache.parquet.column.page.DataPageV2; +import org.apache.parquet.column.page.DictionaryPage; +import org.apache.parquet.column.page.PageReadStore; +import org.apache.parquet.column.page.PageReader; +import org.apache.parquet.compression.CompressionCodecFactory; +import org.apache.parquet.compression.CompressionCodecFactory.BytesInputDecompressor; +import org.apache.parquet.format.DataPageHeader; +import org.apache.parquet.format.DataPageHeaderV2; +import org.apache.parquet.format.DictionaryPageHeader; +import org.apache.parquet.format.PageHeader; +import org.apache.parquet.format.Util; +import org.apache.parquet.format.converter.ParquetMetadataConverter; +import org.apache.parquet.hadoop.metadata.BlockMetaData; +import org.apache.parquet.hadoop.metadata.ColumnChunkMetaData; +import org.apache.parquet.hadoop.metadata.ColumnPath; +import org.apache.parquet.hadoop.metadata.ParquetMetadata; +import org.apache.parquet.io.ParquetDecodingException; +import org.apache.parquet.schema.PrimitiveType; + +/** + * {@link PageReadStore} over one row group's cached column-chunk buffers, so that the vectorized + * column readers decode straight out of the LLAP cache: no ParquetFileReader, and no copy of the + * chunk bytes. + * + * <p><b>Why this is a copy.</b> Parquet does the same thing over a file, but none of it is + * reachable from here: {@code ParquetFileReader.Chunk.readAllPages} is private, the store it fills + * ({@code org.apache.parquet.hadoop.ColumnChunkPageReadStore}) is package-private and so is its + * {@code addColumn}, and the {@link PageReader} it puts in ({@code ColumnChunkPageReader}) is a + * package-private {@code final} class. Only the glue below is re-implemented; page header parsing, + * encoding and statistics conversion, the page value types and decompression are all parquet's own + * public API. + * + * <p><b>On a parquet upgrade.</b> Exactly two members track upstream code, each with a counterpart + * to diff against the new release: + * <ul> + * <li>{@link #readAllPages} mirrors {@code ParquetFileReader.Chunk.readAllPages}: the page-header + * walk, the page-type switch and the mapping of header fields onto {@link DataPageV1}, + * {@link DataPageV2} and {@link DictionaryPage}. A new page type, a new header field or a + * changed page constructor lands here.</li> + * <li>{@link CachedChunkPageReader} mirrors {@code ColumnChunkPageReader}: page queueing and + * lazy decompression. New {@link PageReader} behaviour lands here.</li> + * </ul> + * Also check whether {@link PageReadStore} gained or changed a {@code default} method, since this + * class implements none of them ({@code getRowIndexOffset}, {@code getRowIndexes} and + * {@code close} are all inherited). {@code TestParquetCachedPageReadStore} compares this store page + * for page against the stock one and pins the parquet version, so the upgrade fails the build + * rather than passing with a divergence. + * + * <p>Deliberately unsupported, because LLAP's Parquet path does not use them: the offset index (so + * {@code getFirstRowIndex} and {@code getIndexRowCount} keep their no-offset-index defaults), + * column encryption, and page checksum verification. + * + * <p>How it works: + * <ol> + * <li><b>Input</b>: a {@link ParquetEncodedColumnBatch} holding the already-cached + * {@link MemoryBuffer}s for one row group's projected column chunks, plus the file footer.</li> + * <li><b>Stitching and parsing</b>: per chunk, {@link #chunkBuffers} turns the cache buffers into a + * list of {@link ByteBuffer} slices covering exactly the chunk's byte region; {@link #readAllPages} + * then walks that byte range with {@link Util#readPageHeader}, building {@link DataPageV1} / + * {@link DataPageV2} / {@link DictionaryPage} objects whose payloads are + * {@link ByteBufferInputStream} views over the cache buffers - the page bytes are never copied.</li> + * <li><b>Lazy decompression</b>: each {@link CachedChunkPageReader} keeps the raw bytes and its + * {@link BytesInputDecompressor}, and decompresses only when the vectorized column reader + * actually calls {@link PageReader#readPage()}, so pages that get pruned never pay the codec cost.</li> + * <li><b>Output</b>: the resulting {@code ColumnPath -> PageReader} map backs + * {@link #getPageReader(ColumnDescriptor)}, so parquet's VectorizedColumnReader never notices + * that it is not reading from a file.</li> + * </ol> + */ +class ParquetCachedPageReadStore implements PageReadStore { + + private final Map<ColumnPath, PageReader> readers = new HashMap<>(); + private final long rowCount; + + ParquetCachedPageReadStore(ParquetMetadata footer, ParquetEncodedColumnBatch batch, + CompressionCodecFactory codecFactory, ParquetMetadataConverter converter) throws IOException { + BlockMetaData block = footer.getBlocks().get(batch.rowGroupIx()); + this.rowCount = block.getRowCount(); + String createdBy = footer.getFileMetaData().getCreatedBy(); + ColumnChunkMetaData[] chunks = batch.chunks(); + // pc is the projection index: chunks[pc] and the batch's three buffer arrays are all indexed by + // it, while the footer's block lists columns in file order. Keying on the path keeps the two + // apart, so a projection that drops columns from the middle of the schema still lines up. + for (int pc = 0; pc < chunks.length; ++pc) { + ColumnChunkMetaData chunk = chunks[pc]; + readers.put(chunk.getPath(), readAllPages(chunk, chunkBuffers(batch, pc), createdBy, + codecFactory.getDecompressor(chunk.getCodec()), converter)); + } + } + + /** + * Slices of the cached buffers covering exactly the chunk's byte region, in file order. + * + * <p>This is the only place in the class that touches bytes, and the only place the cache appears + * at all: the {@link MemoryBuffer}s are already-populated LLAP cache memory, so there is no read + * here and nothing to decide - by the time this runs, a cache hit and a miss that + * {@code ParquetEncodedDataReader} had to fetch look exactly the same. + * + * <p>The buffers are cache ranges aligned to absolute file offsets, not to this chunk, so the + * first and last one usually overhang the chunk (the first may even start before it). That is what + * the trimming below is for. + * + * <p>The trimmed slices have to tile the chunk exactly, which is checked as they are built: a + * buffer that does not continue where the previous one ended, or one that reaches past the chunk, + * means the batch is not carrying the buffers the chunk was planned with. Without the check the + * page walk would read the wrong bytes as page bytes, and fail much later with a decoding error + * about a corrupt header. + */ + private static List<ByteBuffer> chunkBuffers(ParquetEncodedColumnBatch batch, int pc) + throws IOException { + ColumnChunkMetaData chunk = batch.chunks()[pc]; + long chunkStart = chunk.getStartingPos(); + long chunkEnd = chunkStart + chunk.getTotalSize(); + MemoryBuffer[] columnBuffers = batch.columnBuffers()[pc]; + long[] bufferOffsets = batch.bufferOffsets()[pc]; + int[] bufferLengths = batch.bufferLengths()[pc]; + List<ByteBuffer> slices = new ArrayList<>(columnBuffers.length); + long covered = chunkStart; + for (int i = 0; i < columnBuffers.length; ++i) { + long bufferStart = bufferOffsets[i]; + long bufferEnd = bufferStart + bufferLengths[i]; + long sliceStart = Math.max(chunkStart, bufferStart); + long sliceEnd = Math.min(chunkEnd, bufferEnd); + if (sliceStart != covered || sliceEnd <= sliceStart) { + throw new IOException("Cached buffer " + (i + 1) + " of " + columnBuffers.length + " for column chunk " + + chunk.getPath() + " covers [" + sliceStart + ", " + sliceEnd + ") of the chunk at [" + + chunkStart + ", " + chunkEnd + "), which does not continue at " + covered); + } + covered = sliceEnd; + // A dup, because the cache buffer is shared: moving position/limit must not be visible to + // another reader of the same buffer. slice() then keeps a view of the trimmed region, so the + // chunk bytes are still the cache's bytes - nothing is copied here or below. + ByteBuffer bb = columnBuffers[i].getByteBufferDup(); + bb.position(bb.position() + (int) (sliceStart - bufferStart)); + bb.limit(bb.position() + (int) (sliceEnd - sliceStart)); + slices.add(bb.slice()); + } + if (covered != chunkEnd) { + throw new IOException("Cached buffers for column chunk " + chunk.getPath() + " cover [" + + chunkStart + ", " + covered + "), but the chunk ends at " + chunkEnd); + } + return slices; + } + + private static PageReader readAllPages(ColumnChunkMetaData chunk, List<ByteBuffer> buffers, + String createdBy, BytesInputDecompressor decompressor, ParquetMetadataConverter converter) + throws IOException { + // Reads across the buffer boundaries as if the chunk were contiguous, which it is not: a page + // header or a payload can straddle two cache buffers. sliceBuffers below hands out views into + // these same buffers, so every page this method builds points at cache memory for as long as it + // lives - the batch has to keep its refs until the consumer is done decoding. + ByteBufferInputStream stream = ByteBufferInputStream.wrap(buffers); + PrimitiveType type = chunk.getPrimitiveType(); + List<DataPage> pages = new ArrayList<>(); + DictionaryPage dictionaryPage = null; + long valuesRead = 0; + // Only data pages count towards valuesRead, so the dictionary page and any page type skipped + // below do not end the walk early; the footer's value count is the only terminator. + while (valuesRead < chunk.getValueCount()) { + PageHeader header = Util.readPageHeader(stream); + int uncompressedSize = header.getUncompressed_page_size(); + int compressedSize = header.getCompressed_page_size(); + switch (header.getType()) { + case DICTIONARY_PAGE: + if (dictionaryPage != null) { + throw new ParquetDecodingException("more than one dictionary page in column " + chunk.getPath()); + } + DictionaryPageHeader dictHeader = header.getDictionary_page_header(); + dictionaryPage = new DictionaryPage(BytesInput.from(stream.sliceBuffers(compressedSize)), + uncompressedSize, dictHeader.getNum_values(), converter.getEncoding(dictHeader.getEncoding())); + break; + case DATA_PAGE: + DataPageHeader v1 = header.getData_page_header(); + pages.add(new DataPageV1(BytesInput.from(stream.sliceBuffers(compressedSize)), v1.getNum_values(), + uncompressedSize, converter.fromParquetStatistics(createdBy, v1.getStatistics(), type), + converter.getEncoding(v1.getRepetition_level_encoding()), + converter.getEncoding(v1.getDefinition_level_encoding()), + converter.getEncoding(v1.getEncoding()))); + valuesRead += v1.getNum_values(); + break; + case DATA_PAGE_V2: Review Comment: do we have any tests for parquet.writer.version=v2, PARQUET_2_0 ? -- This is an automated message from the Apache Git Service. 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