DiffKeyDeltaEncoder (Apache HBase 1.4.11 API)

java.lang.Object
- org.apache.hadoop.hbase.io.encoding.AbstractDataBlockEncoder
- - org.apache.hadoop.hbase.io.encoding.DiffKeyDeltaEncoder

All Implemented Interfaces:

DataBlockEncoder
```
@InterfaceAudience.Private
public class DiffKeyDeltaEncoder
extends AbstractDataBlockEncoder
```
Compress using: - store size of common prefix - save column family once, it is same within HFile - use integer compression for key, value and prefix (7-bit encoding) - use bits to avoid duplication key length, value length and type if it same as previous - store in 3 bits length of timestamp field - allow diff in timestamp instead of actual value Format: - 1 byte: flag - 1-5 bytes: key length (only if FLAG_SAME_KEY_LENGTH is not set in flag) - 1-5 bytes: value length (only if FLAG_SAME_VALUE_LENGTH is not set in flag) - 1-5 bytes: prefix length - ... bytes: rest of the row (if prefix length is small enough) - ... bytes: qualifier (or suffix depending on prefix length) - 1-8 bytes: timestamp or diff - 1 byte: type (only if FLAG_SAME_TYPE is not set in the flag) - ... bytes: value

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`BufferedDataBlockEncoder.BufferedEncodedSeeker<STATE extends BufferedDataBlockEncoder.SeekerState>`
`protected static class`	`BufferedDataBlockEncoder.ClonedSeekerState` Copies only the key part of the keybuffer by doing a deep copy and passes the seeker state members for taking a clone.
`protected static class`	`BufferedDataBlockEncoder.SeekerState`
`protected static class`	`DiffKeyDeltaEncoder.DiffCompressionState`
`protected static class`	`DiffKeyDeltaEncoder.DiffSeekerState`

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.io.encoding.AbstractDataBlockEncoder
AbstractDataBlockEncoder.AbstractEncodedSeeker

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.io.encoding.DataBlockEncoder
DataBlockEncoder.EncodedSeeker

Constructor Summary

Constructors
Constructor and Description

DiffKeyDeltaEncoder()

Constructors
Constructor and Description
`DiffKeyDeltaEncoder()`

Method Summary

Methods
Modifier and Type	Method and Description
`protected void`	`afterDecodingKeyValue(DataInputStream source, ByteBuffer dest, HFileBlockDefaultDecodingContext decodingCtx)`
`protected int`	`afterEncodingKeyValue(Cell cell, DataOutputStream out, HFileBlockDefaultEncodingContext encodingCtx)`
`DataBlockEncoder.EncodedSeeker`	`createSeeker(KeyValue.KVComparator comparator, HFileBlockDecodingContext decodingCtx)` Create a HFileBlock seeker which find KeyValues within a block.
`ByteBuffer`	`decodeKeyValues(DataInputStream source, HFileBlockDecodingContext blkDecodingCtx)` Decode.
`int`	`encode(Cell cell, HFileBlockEncodingContext encodingCtx, DataOutputStream out)` Encodes a KeyValue.
`void`	`endBlockEncoding(HFileBlockEncodingContext encodingCtx, DataOutputStream out, byte[] uncompressedBytesWithHeader)` Ends encoding for a block of KeyValues.
`protected static void`	`ensureSpace(ByteBuffer out, int length)` Asserts that there is at least the given amount of unfilled space remaining in the given buffer.
`ByteBuffer`	`getFirstKeyInBlock(ByteBuffer block)` Return first key in block.
`protected ByteBuffer`	`internalDecodeKeyValues(DataInputStream source, int allocateHeaderLength, int skipLastBytes, HFileBlockDefaultDecodingContext decodingCtx)`
`int`	`internalEncode(Cell cell, HFileBlockDefaultEncodingContext encodingContext, DataOutputStream out)`
`void`	`startBlockEncoding(HFileBlockEncodingContext blkEncodingCtx, DataOutputStream out)` Starts encoding for a block of KeyValues.
`String`	`toString()`

Methods inherited from class org.apache.hadoop.hbase.io.encoding.AbstractDataBlockEncoder
newDataBlockDecodingContext, newDataBlockEncodingContext, postEncoding

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail
- DiffKeyDeltaEncoder
```
public DiffKeyDeltaEncoder()
```

Method Detail

internalEncode

public int internalEncode(Cell cell,
                 HFileBlockDefaultEncodingContext encodingContext,
                 DataOutputStream out)
                   throws IOException

Throws:: IOException

getFirstKeyInBlock
```
public ByteBuffer getFirstKeyInBlock(ByteBuffer block)
```
Description copied from interface: DataBlockEncoder

Return first key in block. Useful for indexing. Typically does not make a deep copy but returns a buffer wrapping a segment of the actual block's byte array. This is because the first key in block is usually stored unencoded.

Parameters:
block - encoded block we want index, the position will not change

Returns:
First key in block.

toString
```
public String toString()
```
Overrides:

toString in class Object

createSeeker

public DataBlockEncoder.EncodedSeeker createSeeker(KeyValue.KVComparator comparator,
                                          HFileBlockDecodingContext decodingCtx)

Description copied from interface: DataBlockEncoder

Create a HFileBlock seeker which find KeyValues within a block.

Parameters:: comparator - what kind of comparison should be used
Returns:: A newly created seeker.

internalDecodeKeyValues

protected ByteBuffer internalDecodeKeyValues(DataInputStream source,
                                 int allocateHeaderLength,
                                 int skipLastBytes,
                                 HFileBlockDefaultDecodingContext decodingCtx)
                                      throws IOException

Throws:: IOException

decodeKeyValues
```
public ByteBuffer decodeKeyValues(DataInputStream source,
                         HFileBlockDecodingContext blkDecodingCtx)
                           throws IOException
```
Description copied from interface: DataBlockEncoder

Decode.

Parameters:
source - Compressed stream of KeyValues.

Returns:
Uncompressed block of KeyValues.

Throws:

IOException - If there is an error in source.

afterEncodingKeyValue

protected final int afterEncodingKeyValue(Cell cell,
                        DataOutputStream out,
                        HFileBlockDefaultEncodingContext encodingCtx)
                                   throws IOException

Parameters:: cell -; out -; encodingCtx -
Returns:: unencoded size added
Throws:: IOException

afterDecodingKeyValue

protected final void afterDecodingKeyValue(DataInputStream source,
                         ByteBuffer dest,
                         HFileBlockDefaultDecodingContext decodingCtx)
                                    throws IOException

Throws:: IOException

ensureSpace
```
protected static void ensureSpace(ByteBuffer out,
               int length)
                           throws EncoderBufferTooSmallException
```
Asserts that there is at least the given amount of unfilled space remaining in the given buffer.

Parameters:
out - typically, the buffer we are writing to
length - the required space in the buffer

Throws:

EncoderBufferTooSmallException - If there are no enough bytes.

startBlockEncoding
```
public void startBlockEncoding(HFileBlockEncodingContext blkEncodingCtx,
                      DataOutputStream out)
                        throws IOException
```
Description copied from interface: DataBlockEncoder

Starts encoding for a block of KeyValues. Call DataBlockEncoder.endBlockEncoding(HFileBlockEncodingContext, DataOutputStream, byte[]) to finish encoding of a block.

Throws:

IOException

encode

public int encode(Cell cell,
         HFileBlockEncodingContext encodingCtx,
         DataOutputStream out)
           throws IOException

Description copied from interface: DataBlockEncoder

Encodes a KeyValue.

Returns:: unencoded kv size written
Throws:: IOException

endBlockEncoding
```
public void endBlockEncoding(HFileBlockEncodingContext encodingCtx,
                    DataOutputStream out,
                    byte[] uncompressedBytesWithHeader)
                      throws IOException
```
Description copied from interface: DataBlockEncoder

Ends encoding for a block of KeyValues. Gives a chance for the encoder to do the finishing stuff for the encoded block. It must be called at the end of block encoding.

Throws:

IOException

Class DiffKeyDeltaEncoder

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.io.encoding.AbstractDataBlockEncoder

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.io.encoding.DataBlockEncoder

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.hbase.io.encoding.AbstractDataBlockEncoder

Methods inherited from class java.lang.Object

Constructor Detail

DiffKeyDeltaEncoder

Method Detail

internalEncode

getFirstKeyInBlock

toString

createSeeker

internalDecodeKeyValues

decodeKeyValues

afterEncodingKeyValue

afterDecodingKeyValue

ensureSpace

startBlockEncoding

encode

endBlockEncoding