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Server functionality for HBase
/*
*
* 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 org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.KeyValue.KVComparator;
import org.apache.hadoop.hbase.fs.HFileSystem;
import org.apache.hadoop.hbase.io.compress.Compression;
import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
import org.apache.hadoop.hbase.io.hfile.HFile.FileInfo;
/**
* Common functionality needed by all versions of {@link HFile} readers.
*/
@InterfaceAudience.Private
@edu.umd.cs.findbugs.annotations.SuppressWarnings(value="URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
public abstract class AbstractHFileReader
implements HFile.Reader, Configurable {
/** Stream to read from. Does checksum verifications in file system */
protected FSDataInputStream istream; // UUF_UNUSED_PUBLIC_OR_PROTECTED_FIELD
/** The file system stream of the underlying {@link HFile} that
* does not do checksum verification in the file system */
protected FSDataInputStream istreamNoFsChecksum; // UUF_UNUSED_PUBLIC_OR_PROTECTED_FIELD
/** 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;
/**
* What kind of data block encoding should be used while reading, writing,
* and handling cache.
*/
protected HFileDataBlockEncoder dataBlockEncoder =
NoOpDataBlockEncoder.INSTANCE;
/** 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 KVComparator comparator = new KVComparator();
/** Size of this file. */
protected final long fileSize;
/** Block cache configuration. */
protected final CacheConfig cacheConf;
/** Path of file */
protected final Path path;
/** File name to be used for block names */
protected final String name;
protected FileInfo fileInfo;
/** The filesystem used for accesing data */
protected HFileSystem hfs;
protected Configuration conf;
@edu.umd.cs.findbugs.annotations.SuppressWarnings(value="URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
protected AbstractHFileReader(Path path, FixedFileTrailer trailer,
final long fileSize, final CacheConfig cacheConf, final HFileSystem hfs,
final Configuration conf) {
this.trailer = trailer;
this.compressAlgo = trailer.getCompressionCodec();
this.cacheConf = cacheConf;
this.fileSize = fileSize;
this.path = path;
this.name = path.getName();
this.hfs = hfs; // URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD
this.conf = conf;
}
@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());
}
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 KVComparator 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 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;
protected final HFile.Reader reader;
public Scanner(final HFile.Reader reader, final boolean cacheBlocks,
final boolean pread, final boolean isCompaction) {
this.reader = reader;
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();
}
@Override
public int seekTo(byte[] key) throws IOException {
return seekTo(key, 0, key.length);
}
@Override
public boolean seekBefore(byte[] key) throws IOException {
return seekBefore(key, 0, key.length);
}
@Override
public int reseekTo(byte[] key) throws IOException {
return reseekTo(key, 0, key.length);
}
@Override
public HFile.Reader getReader() {
return reader;
}
}
/** For testing */
abstract HFileBlock.FSReader getUncachedBlockReader();
public Path getPath() {
return path;
}
@Override
public DataBlockEncoding getDataBlockEncoding() {
return dataBlockEncoder.getDataBlockEncoding();
}
public abstract int getMajorVersion();
@Override
public Configuration getConf() {
return conf;
}
@Override
public void setConf(Configuration conf) {
this.conf = conf;
}
}