paul-rogers commented on a change in pull request #1618: DRILL-6950: Row set-based scan framework URL: https://github.com/apache/drill/pull/1618#discussion_r251218672
########## File path: exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/scan/file/BaseFileScanFramework.java ########## @@ -0,0 +1,177 @@ +/* + * 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.physical.impl.scan.file; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Iterator; +import java.util.List; + +import org.apache.drill.common.exceptions.ExecutionSetupException; +import org.apache.drill.common.exceptions.UserException; +import org.apache.drill.common.expression.SchemaPath; +import org.apache.drill.exec.physical.impl.scan.RowBatchReader; +import org.apache.drill.exec.physical.impl.scan.framework.AbstractScanFramework; +import org.apache.drill.exec.physical.impl.scan.framework.ManagedReader; +import org.apache.drill.exec.physical.impl.scan.framework.SchemaNegotiator; +import org.apache.drill.exec.physical.impl.scan.framework.ShimBatchReader; +import org.apache.drill.exec.store.dfs.DrillFileSystem; +import org.apache.drill.exec.store.dfs.easy.FileWork; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.Path; +import org.apache.hadoop.mapred.FileSplit; + +/** + * Scan framework for a file that implements metadata columns (AKA "implicit" + * columns and partition columns.) + * <p> + * Framework iterators over file descriptions, creating readers at the + * moment they are needed. This allows simpler logic because, at the point of + * reader creation, we have a file system, context and so on. + */ + +public abstract class BaseFileScanFramework<T extends BaseFileScanFramework.FileSchemaNegotiator> + extends AbstractScanFramework<T> { + + static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(BaseFileScanFramework.class); + + /** + * The file schema negotiator adds no behavior at present, but is + * created as a placeholder anticipating the need for file-specific + * behavior later. + */ + + public interface FileSchemaNegotiator extends SchemaNegotiator { + } + + private final List<? extends FileWork> files; + private final Configuration fsConfig; + private List<FileSplit> spilts = new ArrayList<>(); + private Iterator<FileSplit> splitIter; + private Path scanRootDir; + private boolean useLegacyWildcardExpansion = true; + protected DrillFileSystem dfs; + private FileMetadataManager metadataManager; + + public BaseFileScanFramework(List<SchemaPath> projection, + List<? extends FileWork> files, + Configuration fsConf) { + super(projection); + this.files = files; + this.fsConfig = fsConf; + } + + /** + * Specify the selection root for a directory scan, if any. + * Used to populate partition columns. + * @param rootPath Hadoop file path for the directory + */ + + public void setSelectionRoot(Path rootPath) { + this.scanRootDir = rootPath; + } + + /** + * For historical reasons, Drill adds all metadata columns for a wildcard + * query. The project operator then drops those that are not needed. This + * flag disables that behavior if newer versions of Drill don't need the + * "create-then-delete" behavior. + * + * @param flag true to use the old-style expansion, false to not include + * metadata columns when expanding the wildcard column + */ + + public void useLegacyWildcardExpansion(boolean flag) { + useLegacyWildcardExpansion = flag; + } + + @Override + protected void configure() { + super.configure(); + + // Create the Drill file system. + + try { + dfs = context.newFileSystem(fsConfig); + } catch (IOException e) { + throw UserException.dataReadError(e) + .addContext("Failed to create FileSystem") + .build(logger); + } + + // Prepare the list of files. We need the list of paths up + // front to compute the maximum partition. Then, we need to + // iterate over the splits to create readers on demand. + + List<Path> paths = new ArrayList<>(); + for(FileWork work : files) { Review comment: Done ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
