/*
* Copyright 2011 The Apache Software Foundation
*
* 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.hbase.io.hfile;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.io.hfile.HFile.FileInfo;
import org.apache.hadoop.hbase.io.hfile.HFile.Reader;
import org.apache.hadoop.io.RawComparator;
/**
* Common functionality needed by all versions of {@link HFile} readers.
*/
public abstract class AbstractHFileReader implements HFile.Reader {
private static final Log LOG = LogFactory.getLog(AbstractHFileReader.class);
/** Filesystem-level block reader for this HFile format version. */
protected HFileBlock.FSReader fsBlockReader;
/** Stream to read from. */
protected FSDataInputStream istream;
/**
* True if we should close the input stream when done. We don't close it if we
* didn't open it.
*/
protected final boolean closeIStream;
/** Data block index reader keeping the root data index in memory */
protected HFileBlockIndex.BlockIndexReader dataBlockIndexReader;
/** Meta block index reader -- always single level */
protected HFileBlockIndex.BlockIndexReader metaBlockIndexReader;
protected final FixedFileTrailer trailer;
/** Filled when we read in the trailer. */
protected final Compression.Algorithm compressAlgo;
/** Last key in the file. Filled in when we read in the file info */
protected byte [] lastKey = null;
/** Average key length read from file info */
protected int avgKeyLen = -1;
/** Average value length read from file info */
protected int avgValueLen = -1;
/** Key comparator */
protected RawComparator<byte []> comparator;
/** Size of this file. */
protected final long fileSize;
/** Block cache configuration. */
protected final CacheConfig cacheConf;
protected AtomicLong cacheHits = new AtomicLong();
protected AtomicLong blockLoads = new AtomicLong();
protected AtomicLong metaLoads = new AtomicLong();
/** Path of file */
protected final Path path;
/** File name to be used for block names */
protected final String name;
protected FileInfo fileInfo;
/** Prefix of the form cf.<column_family_name> for statistics counters. */
private final String cfStatsPrefix;
protected AbstractHFileReader(Path path, FixedFileTrailer trailer,
final FSDataInputStream fsdis, final long fileSize,
final boolean closeIStream,
final CacheConfig cacheConf) {
this.trailer = trailer;
this.compressAlgo = trailer.getCompressionCodec();
this.cacheConf = cacheConf;
this.fileSize = fileSize;
this.istream = fsdis;
this.closeIStream = closeIStream;
this.path = path;
this.name = path.getName();
cfStatsPrefix = "cf." + parseCfNameFromPath(path.toString());
}
@SuppressWarnings("serial")
public static class BlockIndexNotLoadedException
extends IllegalStateException {
public BlockIndexNotLoadedException() {
// Add a message in case anyone relies on it as opposed to class name.
super("Block index not loaded");
}
}
protected String toStringFirstKey() {
return KeyValue.keyToString(getFirstKey());
}
protected String toStringLastKey() {
return KeyValue.keyToString(getLastKey());
}
/**
* Parse the HFile path to figure out which table and column family
* it belongs to. This is used to maintain read statistics on a
* per-column-family basis.
*
* @param path HFile path name
*/
public static String parseCfNameFromPath(String path) {
String splits[] = path.split("/");
if (splits.length < 2) {
LOG.warn("Could not determine the table and column family of the " +
"HFile path " + path);
return "unknown";
}
return splits[splits.length - 2];
}
public abstract boolean isFileInfoLoaded();
@Override
public String toString() {
return "reader=" + path.toString() +
(!isFileInfoLoaded()? "":
", compression=" + compressAlgo.getName() +
", cacheConf=" + cacheConf +
", firstKey=" + toStringFirstKey() +
", lastKey=" + toStringLastKey()) +
", avgKeyLen=" + avgKeyLen +
", avgValueLen=" + avgValueLen +
", entries=" + trailer.getEntryCount() +
", length=" + fileSize;
}
@Override
public long length() {
return fileSize;
}
/**
* Create a Scanner on this file. No seeks or reads are done on creation. Call
* {@link HFileScanner#seekTo(byte[])} to position an start the read. There is
* nothing to clean up in a Scanner. Letting go of your references to the
* scanner is sufficient. NOTE: Do not use this overload of getScanner for
* compactions.
*
* @param cacheBlocks True if we should cache blocks read in by this scanner.
* @param pread Use positional read rather than seek+read if true (pread is
* better for random reads, seek+read is better scanning).
* @return Scanner on this file.
*/
@Override
public HFileScanner getScanner(boolean cacheBlocks, final boolean pread) {
return getScanner(cacheBlocks, pread, false);
}
/**
* @return the first key in the file. May be null if file has no entries. Note
* that this is not the first row key, but rather the byte form of the
* first KeyValue.
*/
@Override
public byte [] getFirstKey() {
if (dataBlockIndexReader == null) {
throw new BlockIndexNotLoadedException();
}
return dataBlockIndexReader.isEmpty() ? null
: dataBlockIndexReader.getRootBlockKey(0);
}
/**
* TODO left from {@link HFile} version 1: move this to StoreFile after Ryan's
* patch goes in to eliminate {@link KeyValue} here.
*
* @return the first row key, or null if the file is empty.
*/
@Override
public byte[] getFirstRowKey() {
byte[] firstKey = getFirstKey();
if (firstKey == null)
return null;
return KeyValue.createKeyValueFromKey(firstKey).getRow();
}
/**
* TODO left from {@link HFile} version 1: move this to StoreFile after
* Ryan's patch goes in to eliminate {@link KeyValue} here.
*
* @return the last row key, or null if the file is empty.
*/
@Override
public byte[] getLastRowKey() {
byte[] lastKey = getLastKey();
if (lastKey == null)
return null;
return KeyValue.createKeyValueFromKey(lastKey).getRow();
}
/** @return number of KV entries in this HFile */
@Override
public long getEntries() {
return trailer.getEntryCount();
}
/** @return comparator */
@Override
public RawComparator<byte []> getComparator() {
return comparator;
}
/** @return compression algorithm */
@Override
public Compression.Algorithm getCompressionAlgorithm() {
return compressAlgo;
}
/**
* @return the total heap size of data and meta block indexes in bytes. Does
* not take into account non-root blocks of a multilevel data index.
*/
public long indexSize() {
return (dataBlockIndexReader != null ? dataBlockIndexReader.heapSize() : 0)
+ ((metaBlockIndexReader != null) ? metaBlockIndexReader.heapSize()
: 0);
}
@Override
public String getName() {
return name;
}
@Override
public HFileBlockIndex.BlockIndexReader getDataBlockIndexReader() {
return dataBlockIndexReader;
}
@Override
public String getColumnFamilyName() {
return cfStatsPrefix;
}
@Override
public FixedFileTrailer getTrailer() {
return trailer;
}
@Override
public FileInfo loadFileInfo() throws IOException {
return fileInfo;
}
/**
* An exception thrown when an operation requiring a scanner to be seeked
* is invoked on a scanner that is not seeked.
*/
@SuppressWarnings("serial")
public static class NotSeekedException extends IllegalStateException {
public NotSeekedException() {
super("Not seeked to a key/value");
}
}
protected static abstract class Scanner implements HFileScanner {
protected ByteBuffer blockBuffer;
protected boolean cacheBlocks;
protected final boolean pread;
protected final boolean isCompaction;
protected int currKeyLen;
protected int currValueLen;
protected int currMemstoreTSLen;
protected long currMemstoreTS;
protected int blockFetches;
public Scanner(final boolean cacheBlocks,
final boolean pread, final boolean isCompaction) {
this.cacheBlocks = cacheBlocks;
this.pread = pread;
this.isCompaction = isCompaction;
}
@Override
public boolean isSeeked(){
return blockBuffer != null;
}
@Override
public String toString() {
return "HFileScanner for reader " + String.valueOf(getReader());
}
protected void assertSeeked() {
if (!isSeeked())
throw new NotSeekedException();
}
}
/** For testing */
HFileBlock.FSReader getUncachedBlockReader() {
return fsBlockReader;
}
public Path getPath() {
return path;
}
}