| /* |
| * 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.drill.exec.store.parquet.columnreaders; |
| |
| import org.apache.drill.common.exceptions.ExecutionSetupException; |
| import org.apache.drill.exec.vector.BitVector; |
| import org.apache.parquet.column.ColumnDescriptor; |
| import org.apache.parquet.format.SchemaElement; |
| import org.apache.parquet.hadoop.metadata.ColumnChunkMetaData; |
| |
| final class BitReader extends ColumnReader<BitVector> { |
| |
| BitReader(ParquetRecordReader parentReader, ColumnDescriptor descriptor, ColumnChunkMetaData columnChunkMetaData, |
| boolean fixedLength, BitVector v, SchemaElement schemaElement) throws ExecutionSetupException { |
| super(parentReader, descriptor, columnChunkMetaData, fixedLength, v, schemaElement); |
| } |
| |
| @Override |
| protected void readField(long recordsToReadInThisPass) { |
| |
| recordsReadInThisIteration = Math.min(pageReader.pageValueCount |
| - pageReader.valuesRead, recordsToReadInThisPass - valuesReadInCurrentPass); |
| |
| // A more optimized reader for bit columns was removed to fix the bug |
| // DRILL-2031. It attempted to copy large runs of values directly from the |
| // decompressed parquet stream into a BitVector. This was complicated by |
| // parquet not always breaking a page on a row number divisible by 8. In |
| // this case the batch would have to be cut off early or we would have to |
| // copy the next page byte-by-byte with a bit shift to move the values into |
| // the correct position (to make the value vector one contiguous buffer of |
| // data). As page boundaries do not line up across columns, cutting off a |
| // batch at every page boundary of a bit column could be costly with many |
| // such pages, so we opted to try to shift the bits when necessary. |
| // |
| // In the end, this was too much complexity for not enough performance |
| // benefit, for now this reader has been moved to use the higher level value |
| // by value reader provided by the parquet library. |
| for (int i = 0; i < recordsReadInThisIteration; i++){ |
| valueVec.getMutator().setSafe(i + valuesReadInCurrentPass, |
| pageReader.getValueReader().readBoolean() ? 1 : 0 ); |
| } |
| } |
| } |