DiffKeyDeltaEncoder (Apache HBase 1.2.12 API)

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

All Implemented Interfaces:

DataBlockEncoder
```
@InterfaceAudience.Private
public class DiffKeyDeltaEncoder
extends BufferedDataBlockEncoder
```
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 DiffKeyDeltaEncoder.DiffCompressionState

protected static class DiffKeyDeltaEncoder.DiffSeekerState
- Nested classes/interfaces inherited from class org.apache.hadoop.hbase.io.encoding.BufferedDataBlockEncoder
  BufferedDataBlockEncoder.BufferedEncodedSeeker<STATE extends BufferedDataBlockEncoder.SeekerState>, BufferedDataBlockEncoder.ClonedSeekerState, BufferedDataBlockEncoder.SeekerState
- Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.io.encoding.DataBlockEncoder
  DataBlockEncoder.EncodedSeeker

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`DiffKeyDeltaEncoder.DiffCompressionState`
`protected static class`	`DiffKeyDeltaEncoder.DiffSeekerState`

Field Summary

Fields
Modifier and Type	Field and Description
`(package private) static int`	`FLAG_SAME_KEY_LENGTH`
`(package private) static int`	`FLAG_SAME_TYPE`
`(package private) static int`	`FLAG_SAME_VALUE_LENGTH`
`(package private) static int`	`FLAG_TIMESTAMP_IS_DIFF`
`(package private) static int`	`FLAG_TIMESTAMP_SIGN`
`(package private) static int`	`MASK_TIMESTAMP_LENGTH`
`(package private) static int`	`SHIFT_TIMESTAMP_LENGTH`

Constructor Summary

Constructors
Constructor and Description

DiffKeyDeltaEncoder()

Constructors
Constructor and Description
`DiffKeyDeltaEncoder()`

Method Summary

Methods
Modifier and Type	Method and Description
`private int`	`compressSingleKeyValue(DataOutputStream out, Cell cell, Cell prevCell)`
`DataBlockEncoder.EncodedSeeker`	`createSeeker(KeyValue.KVComparator comparator, HFileBlockDecodingContext decodingCtx)` Create a HFileBlock seeker which find KeyValues within a block.
`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)`
`String`	`toString()`
`private void`	`uncompressSingleKeyValue(DataInputStream source, ByteBuffer buffer, DiffKeyDeltaEncoder.DiffCompressionState state)`

Methods inherited from class org.apache.hadoop.hbase.io.encoding.BufferedDataBlockEncoder
afterDecodingKeyValue, afterEncodingKeyValue, decodeKeyValues, encode, endBlockEncoding, ensureSpace, newDataBlockDecodingContext, newDataBlockEncodingContext, startBlockEncoding

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

Field Detail
- FLAG_SAME_KEY_LENGTH
```
static final int FLAG_SAME_KEY_LENGTH
```
  See Also:
  Constant Field Values
- FLAG_SAME_VALUE_LENGTH
```
static final int FLAG_SAME_VALUE_LENGTH
```
  See Also:
  Constant Field Values
- FLAG_SAME_TYPE
```
static final int FLAG_SAME_TYPE
```
  See Also:
  Constant Field Values
- FLAG_TIMESTAMP_IS_DIFF
```
static final int FLAG_TIMESTAMP_IS_DIFF
```
  See Also:
  Constant Field Values
- MASK_TIMESTAMP_LENGTH
```
static final int MASK_TIMESTAMP_LENGTH
```
  See Also:
  Constant Field Values
- SHIFT_TIMESTAMP_LENGTH
```
static final int SHIFT_TIMESTAMP_LENGTH
```
  See Also:
  Constant Field Values
- FLAG_TIMESTAMP_SIGN
```
static final int FLAG_TIMESTAMP_SIGN
```
  See Also:
  Constant Field Values

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

Method Detail

uncompressSingleKeyValue

private void uncompressSingleKeyValue(DataInputStream source,
                            ByteBuffer buffer,
                            DiffKeyDeltaEncoder.DiffCompressionState state)
                               throws IOException,
                                      EncoderBufferTooSmallException

Throws:: IOException; EncoderBufferTooSmallException

internalEncode

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

Specified by:: internalEncode in class BufferedDataBlockEncoder
Throws:: IOException

compressSingleKeyValue

private int compressSingleKeyValue(DataOutputStream out,
                         Cell cell,
                         Cell prevCell)
                            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

Specified by:: internalDecodeKeyValues in class BufferedDataBlockEncoder
Throws:: IOException

Class DiffKeyDeltaEncoder

Nested Class Summary

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

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

Field Summary

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

FLAG_SAME_KEY_LENGTH

FLAG_SAME_VALUE_LENGTH

FLAG_SAME_TYPE

FLAG_TIMESTAMP_IS_DIFF

MASK_TIMESTAMP_LENGTH

SHIFT_TIMESTAMP_LENGTH

FLAG_TIMESTAMP_SIGN

Constructor Detail

DiffKeyDeltaEncoder

Method Detail

uncompressSingleKeyValue

internalEncode

compressSingleKeyValue

getFirstKeyInBlock

toString

createSeeker

internalDecodeKeyValues