jbewing commented on code in PR #15373: URL: https://github.com/apache/iceberg/pull/15373#discussion_r2850616822
########## arrow/src/main/java/org/apache/iceberg/arrow/vectorized/parquet/VectorizedByteStreamSplitValuesReader.java: ########## @@ -0,0 +1,145 @@ +/* + * 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.EOFException; +import java.io.UncheckedIOException; +import java.nio.ByteBuffer; +import java.nio.ByteOrder; +import org.apache.arrow.vector.FieldVector; +import org.apache.parquet.bytes.ByteBufferInputStream; +import org.apache.parquet.column.values.ValuesReader; +import org.apache.parquet.io.api.Binary; + +/** + * A {@link VectorizedValuesReader} implementation for the encoding type BYTE_STREAM_SPLIT. This is + * adapted from Parquet's ByteStreamSplitValuesReader. + * + * @see <a + * href="https://parquet.apache.org/docs/file-format/data-pages/encodings/#byte-stream-split-byte_stream_split--9";> + * Parquet format encodings: BYTE_STREAM_SPLIT</a> + */ +public class VectorizedByteStreamSplitValuesReader extends ValuesReader + implements VectorizedValuesReader { + + private final int elementSizeInBytes; + private int totalBytesInStream; + private ByteBufferInputStream dataStream; + private ByteBuffer decodedDataStream; + + public VectorizedByteStreamSplitValuesReader(int elementSizeInBytes) { + this.elementSizeInBytes = elementSizeInBytes; + } + + @Override + public void initFromPage(int ignoredValueCount, ByteBufferInputStream in) { + this.totalBytesInStream = in.available(); + this.dataStream = in; + } + + @Override + public int readInteger() { + ensureDecoded(); + return decodedDataStream.getInt(); + } + + @Override + public long readLong() { + ensureDecoded(); + return decodedDataStream.getLong(); + } + + @Override + public float readFloat() { + ensureDecoded(); + return decodedDataStream.getFloat(); + } + + @Override + public double readDouble() { + ensureDecoded(); + return decodedDataStream.getDouble(); + } + + @Override + public Binary readBinary(int len) { + ensureDecoded(); + byte[] bytes = new byte[len]; + decodedDataStream.get(bytes); + return Binary.fromConstantByteArray(bytes); + } + + @Override + public void readIntegers(int total, FieldVector vec, int rowId) { + readBatch(total, vec, rowId); + } + + @Override + public void readLongs(int total, FieldVector vec, int rowId) { + readBatch(total, vec, rowId); + } + + @Override + public void readFloats(int total, FieldVector vec, int rowId) { + readBatch(total, vec, rowId); + } + + @Override + public void readDoubles(int total, FieldVector vec, int rowId) { + readBatch(total, vec, rowId); + } + + @Override + public void skip() { + throw new UnsupportedOperationException("skip is not supported"); + } + + private void readBatch(int total, FieldVector vec, int rowId) { + ensureDecoded(); + int bytesToRead = total * elementSizeInBytes; + long destOffset = (long) rowId * elementSizeInBytes; + ByteBuffer slice = decodedDataStream.slice(); + slice.limit(bytesToRead); + vec.getDataBuffer().setBytes(destOffset, slice); + decodedDataStream.position(decodedDataStream.position() + bytesToRead); + } + + private void ensureDecoded() { + if (decodedDataStream == null) { + this.decodedDataStream = decode(totalBytesInStream / elementSizeInBytes); + } + } + + private ByteBuffer decode(int valuesCount) { + ByteBuffer encoded; + try { + encoded = dataStream.slice(totalBytesInStream).slice(); + } catch (EOFException e) { + throw new UncheckedIOException("Failed to read bytes from stream", e); + } + byte[] decoded = new byte[encoded.limit()]; + int destByteIndex = 0; + for (int srcValueIndex = 0; srcValueIndex < valuesCount; srcValueIndex++) { + for (int stream = 0; stream < elementSizeInBytes; stream++, destByteIndex++) { + decoded[destByteIndex] = encoded.get(srcValueIndex + stream * valuesCount); + } + } + return ByteBuffer.wrap(decoded).order(ByteOrder.LITTLE_ENDIAN); Review Comment: Good callout there. To my knowledge though, this would be the _first_ usage of the Java assert keyword in this codebase and I'm not seeing any compile flags or run modes that enables these at runtime which makes me think that while it may be useful for documenting invariants, it would be effectively dead code. Here's the ripgrep query that I ran from the iceberg root: ```bash ❯ rg -n --pcre2 --type java -C 3 '^(?!\s*//)(?!\s*\*)(?:[^/]|/(?!/))*\bassert\s' . ./spark/v3.5/spark-extensions/src/test/java/org/apache/iceberg/spark/extensions/TestAddFilesProcedure.java 814- sql( 815- "SELECT id, `naMe`, dept, subdept from %s WHERE `naMe` = 'John Doe' ORDER BY id", 816- sourceTableName)) 817: .as("If this assert breaks it means that Spark has fixed the pushdown issue") 818- .isEmpty(); 819- 820- // Pushdown works for iceberg ./spark/v4.0/spark-extensions/src/test/java/org/apache/iceberg/spark/extensions/TestAddFilesProcedure.java 812- sql( 813- "SELECT id, `naMe`, dept, subdept from %s WHERE `naMe` = 'John Doe' ORDER BY id", 814- sourceTableName)) 815: .as("If this assert breaks it means that Spark has fixed the pushdown issue") 816- .isEmpty(); 817- 818- // Pushdown works for iceberg ./spark/v4.1/spark-extensions/src/test/java/org/apache/iceberg/spark/extensions/TestAddFilesProcedure.java 812- sql( 813- "SELECT id, `naMe`, dept, subdept from %s WHERE `naMe` = 'John Doe' ORDER BY id", 814- sourceTableName)) 815: .as("If this assert breaks it means that Spark has fixed the pushdown issue") 816- .isEmpty(); 817- 818- // Pushdown works for iceberg ./spark/v3.4/spark-extensions/src/test/java/org/apache/iceberg/spark/extensions/TestAddFilesProcedure.java 814- sql( 815- "SELECT id, `naMe`, dept, subdept from %s WHERE `naMe` = 'John Doe' ORDER BY id", 816- sourceTableName)) 817: .as("If this assert breaks it means that Spark has fixed the pushdown issue") 818- .isEmpty(); 819- 820- // Pushdown works for iceberg ``` Given that we can't really get any valuable results from the keyword, the runtime checking here would strictly introduce a performance regression. All to say: if you think it's valuable enough to include those, we can. It will come with runtime cost though and what we have here isn't less safe than what the parquet-java impl has since I can't imagine anyone will be running with `-ea` in the wild -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
