org.apache.hadoop.hbase.io.hfile

Class HFileReaderV2

java.lang.Object

org.apache.hadoop.hbase.io.hfile.AbstractHFileReader

org.apache.hadoop.hbase.io.hfile.HFileReaderV2

All Implemented Interfaces:

Closeable, AutoCloseable, HFile.CachingBlockReader, HFile.Reader

@InterfaceAudience.Private
public class HFileReaderV2
extends AbstractHFileReader

HFile reader for version 2.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	HFileReaderV2.AbstractScannerV2
protected static class	HFileReaderV2.EncodedScannerV2 ScannerV2 that operates on encoded data blocks.
protected static class	HFileReaderV2.ScannerV2 Implementation of HFileScanner interface.

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.io.hfile.AbstractHFileReader

AbstractHFileReader.BlockIndexNotLoadedException, AbstractHFileReader.NotSeekedException, AbstractHFileReader.Scanner

Field Summary

Fields inherited from class org.apache.hadoop.hbase.io.hfile.AbstractHFileReader

avgKeyLen, avgValueLen, cacheConf, comparator, compressAlgo, dataBlockEncoder, dataBlockIndexReader, fileInfo, fileSize, hfs, istream, istreamNoFsChecksum, lastKey, metaBlockIndexReader, name, path, trailer

Constructor Summary

Constructors

Constructor and Description
HFileReaderV2(org.apache.hadoop.fs.Path path, FixedFileTrailer trailer, FSDataInputStreamWrapper fsdis, long size, CacheConfig cacheConf, HFileSystem hfs) Opens a HFile.

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
void	close(boolean evictOnClose) Close method with optional evictOnClose
DataInput	getDeleteBloomFilterMetadata() Retrieves delete family Bloom filter metadata as appropriate for each HFile version.
DataInput	getGeneralBloomFilterMetadata() Returns a buffer with the Bloom filter metadata.
byte[]	getLastKey()
ByteBuffer	getMetaBlock(String metaBlockName, boolean cacheBlock)
HFileScanner	getScanner(boolean cacheBlocks, boolean pread, boolean isCompaction) Create a Scanner on this file.
boolean	hasMVCCInfo()
boolean	isFileInfoLoaded()
byte[]	midkey()
HFileBlock	readBlock(long dataBlockOffset, long onDiskBlockSize, boolean cacheBlock, boolean pread, boolean isCompaction, BlockType expectedBlockType) Read in a file block.

Methods inherited from class org.apache.hadoop.hbase.io.hfile.AbstractHFileReader

getComparator, getCompressionAlgorithm, getDataBlockEncoding, getDataBlockIndexReader, getEntries, getFirstKey, getFirstRowKey, getLastRowKey, getName, getPath, getScanner, getTrailer, indexSize, length, loadFileInfo, toString, toStringFirstKey, toStringLastKey

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

HFileReaderV2

public HFileReaderV2(org.apache.hadoop.fs.Path path,
             FixedFileTrailer trailer,
             FSDataInputStreamWrapper fsdis,
             long size,
             CacheConfig cacheConf,
             HFileSystem hfs)
              throws IOException

Opens a HFile. You must load the index before you can use it by calling AbstractHFileReader.loadFileInfo().

Parameters:

path - Path to HFile.

trailer - File trailer.

fsdis - input stream.

size - Length of the stream.

cacheConf - Cache configuration.

preferredEncodingInCache - the encoding to use in cache in case we have a choice. If the file is already encoded on disk, we will still use its on-disk encoding in cache.

Throws:

IOException

Method Detail

getScanner

public HFileScanner getScanner(boolean cacheBlocks,
                      boolean pread,
                      boolean isCompaction)

Create a Scanner on this file. No seeks or reads are done on creation. Call 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.

Parameters:

cacheBlocks - True if we should cache blocks read in by this scanner.

pread - Use positional read rather than seek+read if true (pread is better for random reads, seek+read is better scanning).

isCompaction - is scanner being used for a compaction?

Returns:

Scanner on this file.

getMetaBlock

public ByteBuffer getMetaBlock(String metaBlockName,
                      boolean cacheBlock)
                        throws IOException

Parameters:

metaBlockName -

cacheBlock - Add block to cache, if found

Returns:

block wrapped in a ByteBuffer, with header skipped

Throws:

IOException

readBlock

public HFileBlock readBlock(long dataBlockOffset,
                   long onDiskBlockSize,
                   boolean cacheBlock,
                   boolean pread,
                   boolean isCompaction,
                   BlockType expectedBlockType)
                     throws IOException

Read in a file block.

Parameters:

dataBlockOffset - offset to read.

onDiskBlockSize - size of the block

cacheBlock -

pread - Use positional read instead of seek+read (positional is better doing random reads whereas seek+read is better scanning).

isCompaction - is this block being read as part of a compaction

expectedBlockType - the block type we are expecting to read with this read operation, or null to read whatever block type is available and avoid checking (that might reduce caching efficiency of encoded data blocks)

Returns:

Block wrapped in a ByteBuffer.

Throws:

IOException

hasMVCCInfo

public boolean hasMVCCInfo()

getLastKey

public byte[] getLastKey()

Returns:

Last key in the file. May be null if file has no entries. Note that this is not the last row key, but rather the byte form of the last KeyValue.

midkey

public byte[] midkey()
              throws IOException

Returns:

Midkey for this file. We work with block boundaries only so returned midkey is an approximation only.

Throws:

IOException

close

public void close()
           throws IOException

Throws:

IOException

close

public void close(boolean evictOnClose)
           throws IOException

Description copied from interface: HFile.Reader

Close method with optional evictOnClose

Throws:

IOException

getGeneralBloomFilterMetadata

public DataInput getGeneralBloomFilterMetadata()
                                        throws IOException

Returns a buffer with the Bloom filter metadata. The caller takes ownership of the buffer.

Throws:

IOException

getDeleteBloomFilterMetadata

public DataInput getDeleteBloomFilterMetadata()
                                       throws IOException

Description copied from interface: HFile.Reader

Retrieves delete family Bloom filter metadata as appropriate for each HFile version. Knows nothing about how that metadata is structured.

Throws:

IOException

isFileInfoLoaded

public boolean isFileInfoLoaded()

Specified by:

isFileInfoLoaded in class AbstractHFileReader