Package org.apache.hadoop.hbase.io

Class HalfStoreFileReader

java.lang.Object

org.apache.hadoop.hbase.regionserver.StoreFileReader

org.apache.hadoop.hbase.io.HalfStoreFileReader

@Private
public class HalfStoreFileReader
extends StoreFileReader

A facade for a HFile.Reader that serves up either the top or bottom half of a HFile where 'bottom' is the first half of the file containing the keys that sort lowest and 'top' is the second half of the file with keys that sort greater than those of the bottom half. The top includes the split files midkey, of the key that follows if it does not exist in the file.

This type works in tandem with the Reference type. This class is used reading while Reference is used writing.

This file is not splitable. Calls to midKey() return null.

Field Summary

Fields

Modifier and Type	Field	Description
private AtomicBoolean	closed
private Optional<ExtendedCell>	firstKey
private boolean	firstKeySeeked
private static final org.slf4j.Logger	LOG
private final ExtendedCell	splitCell
protected final byte[]	splitkey
(package private) final boolean	top

Fields inherited from class org.apache.hadoop.hbase.regionserver.StoreFileReader

bloomFilterType, conf, deleteFamilyBloomFilter, generalBloomFilter, reader, sequenceID, timeRange

Constructor Summary

Constructors

Constructor	Description
HalfStoreFileReader(ReaderContext context, HFileInfo fileInfo, CacheConfig cacheConf, Reference r, StoreFileInfo storeFileInfo, org.apache.hadoop.conf.Configuration conf)	Creates a half file reader for a hfile referred to by an hfilelink.

Method Summary

Modifier and Type	Method	Description
void	close(boolean evictOnClose)	Overrides close method to handle cache evictions for the referred file.
long	getEntries()
long	getFilterEntries()	The number of Bloom filter entries in this store file, or an estimate thereof, if the Bloom filter is not loaded.
Optional<ExtendedCell>	getFirstKey()
Optional<ExtendedCell>	getLastKey()
protected HFileScanner	getScanner(boolean cacheBlocks, boolean pread, boolean isCompaction)	Will be overridden in HalfStoreFileReader
protected boolean	isTop()
Optional<ExtendedCell>	midKey()
boolean	passesKeyRangeFilter(Scan scan)	Checks whether the given scan rowkey range overlaps with the current storefile's

Methods inherited from class org.apache.hadoop.hbase.regionserver.StoreFileReader

getBloomFilterType, getComparator, getDeleteFamilyCnt, getHFileMinorVersion, getHFileReader, getHFileVersion, getLastRowKey, getMaxTimestamp, getPrefixLength, getReaderContext, getSequenceID, getStoreFileScanner, getTotalBloomSize, getTotalUncompressedBytes, indexSize, isBulkLoaded, isPrimaryReplicaReader, length, loadBloomfilter, loadFileInfo, passesDeleteFamilyBloomFilter, passesGeneralRowColBloomFilter, setBulkLoaded, setSequenceID

Methods inherited from class java.lang.Object

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

Field Details

LOG

private static final org.slf4j.Logger LOG

top

final boolean top

splitkey

protected final byte[] splitkey

splitCell

private final ExtendedCell splitCell

firstKey

private Optional<ExtendedCell> firstKey

firstKeySeeked

private boolean firstKeySeeked

closed

private AtomicBoolean closed

Constructor Details

HalfStoreFileReader

public HalfStoreFileReader(ReaderContext context,
 HFileInfo fileInfo,
 CacheConfig cacheConf,
 Reference r,
 StoreFileInfo storeFileInfo,
 org.apache.hadoop.conf.Configuration conf)
                    throws IOException

Creates a half file reader for a hfile referred to by an hfilelink.

Parameters:

context - Reader context info

fileInfo - HFile info

cacheConf - CacheConfig

r - original reference file (contains top or bottom)

conf - Configuration

Throws:

IOException

Method Details

isTop

protected boolean isTop()

getScanner

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

Description copied from class: StoreFileReader

Will be overridden in HalfStoreFileReader

Overrides:

getScanner in class StoreFileReader

passesKeyRangeFilter

public boolean passesKeyRangeFilter(Scan scan)

Description copied from class: StoreFileReader

Checks whether the given scan rowkey range overlaps with the current storefile's

Overrides:

passesKeyRangeFilter in class StoreFileReader

Parameters:

scan - the scan specification. Used to determine the rowkey range.

Returns:

true if there is overlap, false otherwise

getLastKey

public Optional<ExtendedCell> getLastKey()

Overrides:

getLastKey in class StoreFileReader

midKey

public Optional<ExtendedCell> midKey()
                              throws IOException

Overrides:

midKey in class StoreFileReader

Throws:

IOException

getFirstKey

public Optional<ExtendedCell> getFirstKey()

Overrides:

getFirstKey in class StoreFileReader

getEntries

public long getEntries()

Overrides:

getEntries in class StoreFileReader

getFilterEntries

public long getFilterEntries()

Description copied from class: StoreFileReader

The number of Bloom filter entries in this store file, or an estimate thereof, if the Bloom filter is not loaded. This always returns an upper bound of the number of Bloom filter entries.

Overrides:

getFilterEntries in class StoreFileReader

Returns:

an estimate of the number of Bloom filter entries in this file

close

public void close(boolean evictOnClose)
           throws IOException

Overrides close method to handle cache evictions for the referred file. If evictionOnClose is true, we will seek to the block containing the splitCell and evict all blocks from offset 0 up to that block offset if this is a bottom half reader, or the from the split block offset up to the end of the file if this is a top half reader.

Overrides:

close in class StoreFileReader

Parameters:

evictOnClose - true if it should evict the file blocks from the cache.

Throws:

IOException