org.apache.hadoop.hive.ql.io.HdfsUtils Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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
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package org.apache.hadoop.hive.ql.io;
import java.io.IOException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.hive.shims.HadoopShims;
import org.apache.hadoop.hive.shims.ShimLoader;
public class HdfsUtils {
private static final HadoopShims SHIMS = ShimLoader.getHadoopShims();
private static final Logger LOG = LoggerFactory.getLogger(HdfsUtils.class);
public static Object getFileId(
FileSystem fileSystem, Path path, boolean allowSynthetic) throws IOException {
if (fileSystem instanceof DistributedFileSystem) {
return SHIMS.getFileId(fileSystem, path.toUri().getPath());
}
if (!allowSynthetic) {
LOG.warn("Cannot get unique file ID from "
+ fileSystem.getClass().getSimpleName() + "; returning null");
return null;
}
FileStatus fs = fileSystem.getFileStatus(path);
return new SyntheticFileId(path, fs.getLen(), fs.getModificationTime());
}
public static long createFileId(String pathStr, FileStatus fs, boolean doLog, String fsName) {
int nameHash = pathStr.hashCode();
long fileSize = fs.getLen(), modTime = fs.getModificationTime();
int fileSizeHash = (int)(fileSize ^ (fileSize >>> 32)),
modTimeHash = (int)(modTime ^ (modTime >>> 32)),
combinedHash = modTimeHash ^ fileSizeHash;
long id = (((long)nameHash & 0xffffffffL) << 32) | ((long)combinedHash & 0xffffffffL);
if (doLog) {
LOG.warn("Cannot get unique file ID from " + fsName + "; using " + id
+ " (" + pathStr + "," + nameHash + "," + fileSize + ")");
}
return id;
}
// TODO: this relies on HDFS not changing the format; we assume if we could get inode ID, this
// is still going to work. Otherwise, file IDs can be turned off. Later, we should use
// as public utility method in HDFS to obtain the inode-based path.
private static String HDFS_ID_PATH_PREFIX = "/.reserved/.inodes/";
public static Path getFileIdPath(
FileSystem fileSystem, Path path, long fileId) {
return ((fileSystem instanceof DistributedFileSystem))
? new Path(HDFS_ID_PATH_PREFIX + fileId) : path;
}
}