org.apache.hadoop.hive.ql.io.RCFileRecordReader Maven / Gradle / Ivy
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/**
* 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.ql.io;
import java.io.IOException;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.ql.io.RCFile.KeyBuffer;
import org.apache.hadoop.hive.ql.io.RCFile.Reader;
import org.apache.hadoop.hive.serde2.columnar.BytesRefArrayWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.mapred.FileSplit;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.util.ReflectionUtils;
/**
* RCFileRecordReader.
*
* @param
* @param
*/
public class RCFileRecordReader
implements RecordReader {
private final Reader in;
private final long start;
private final long end;
private boolean more = true;
protected Configuration conf;
private final FileSplit split;
private final boolean useCache;
private static RCFileSyncCache syncCache = new RCFileSyncCache();
private static final class RCFileSyncEntry {
long end;
long endSync;
}
private static final class RCFileSyncCache {
private final Map cache;
public RCFileSyncCache() {
cache = Collections.synchronizedMap(new WeakHashMap());
}
public void put(FileSplit split, long endSync) {
Path path = split.getPath();
long end = split.getStart() + split.getLength();
String key = path.toString()+"+"+String.format("%d",end);
RCFileSyncEntry entry = new RCFileSyncEntry();
entry.end = end;
entry.endSync = endSync;
if(entry.endSync >= entry.end) {
cache.put(key, entry);
}
}
public long get(FileSplit split) {
Path path = split.getPath();
long start = split.getStart();
String key = path.toString()+"+"+String.format("%d",start);
RCFileSyncEntry entry = cache.get(key);
if(entry != null) {
return entry.endSync;
}
return -1;
}
}
public RCFileRecordReader(Configuration conf, FileSplit split)
throws IOException {
Path path = split.getPath();
FileSystem fs = path.getFileSystem(conf);
this.in = new RCFile.Reader(fs, path, conf);
this.end = split.getStart() + split.getLength();
this.conf = conf;
this.split = split;
useCache = HiveConf.getBoolVar(conf, HiveConf.ConfVars.HIVEUSERCFILESYNCCACHE);
if (split.getStart() > in.getPosition()) {
long oldSync = useCache ? syncCache.get(split) : -1;
if(oldSync == -1) {
in.sync(split.getStart()); // sync to start
} else {
in.seek(oldSync);
}
}
this.start = in.getPosition();
more = start < end;
}
public Class getKeyClass() {
return LongWritable.class;
}
public Class getValueClass() {
return BytesRefArrayWritable.class;
}
public LongWritable createKey() {
return (LongWritable) ReflectionUtils.newInstance(getKeyClass(), conf);
}
public BytesRefArrayWritable createValue() {
return (BytesRefArrayWritable) ReflectionUtils.newInstance(getValueClass(),
conf);
}
public boolean nextBlock() throws IOException {
return in.nextBlock();
}
@Override
public boolean next(LongWritable key, BytesRefArrayWritable value)
throws IOException {
more = next(key);
if (more) {
in.getCurrentRow(value);
}
return more;
}
protected boolean next(LongWritable key) throws IOException {
if (!more) {
return false;
}
more = in.next(key);
long lastSeenSyncPos = in.lastSeenSyncPos();
if (lastSeenSyncPos >= end) {
if(useCache) {
syncCache.put(split, lastSeenSyncPos);
}
more = false;
return more;
}
return more;
}
/**
* Return the progress within the input split.
*
* @return 0.0 to 1.0 of the input byte range
*/
public float getProgress() throws IOException {
if (end == start) {
return 0.0f;
} else {
return Math.min(1.0f, (in.getPosition() - start) / (float) (end - start));
}
}
public long getPos() throws IOException {
return in.getPosition();
}
public KeyBuffer getKeyBuffer() {
return in.getCurrentKeyBufferObj();
}
protected void seek(long pos) throws IOException {
in.seek(pos);
}
public void sync(long pos) throws IOException {
in.sync(pos);
}
public void resetBuffer() {
in.resetBuffer();
}
public long getStart() {
return start;
}
public void close() throws IOException {
in.close();
}
}