PlainTableConfig

java.lang.Object
- org.rocksdb.TableFormatConfig
- - org.rocksdb.PlainTableConfig

```
public class PlainTableConfig
extends TableFormatConfig
```
The config for plain table sst format.
PlainTable is a RocksDB's SST file format optimized for low query latency on pure-memory or really low-latency media.

It also support prefix hash feature.

字段概要

字段
限定符和类型	字段和说明
`static int`	`DEFAULT_BLOOM_BITS_PER_KEY`
`static EncodingType`	`DEFAULT_ENCODING_TYPE`
`static boolean`	`DEFAULT_FULL_SCAN_MODE`
`static double`	`DEFAULT_HASH_TABLE_RATIO`
`static int`	`DEFAULT_HUGE_TLB_SIZE`
`static int`	`DEFAULT_INDEX_SPARSENESS`
`static boolean`	`DEFAULT_STORE_INDEX_IN_FILE`
`static int`	`VARIABLE_LENGTH`

构造器概要

构造器
构造器和说明

PlainTableConfig()

构造器
构造器和说明
`PlainTableConfig()`

方法概要

所有方法实例方法具体方法
限定符和类型	方法和说明
`int`	`bloomBitsPerKey()`
`EncodingType`	`encodingType()` Returns the active EncodingType
`boolean`	`fullScanMode()` Return if full scan mode is active
`double`	`hashTableRatio()`
`int`	`hugePageTlbSize()` Returns the value for huge page tlb size
`long`	`indexSparseness()`
`int`	`keySize()`
`protected long`	`newTableFactoryHandle()` This function should only be called by Options.setTableFormatConfig(), which will create a c++ shared-pointer to the c++ TableFactory that associated with the Java TableFormatConfig.
`PlainTableConfig`	`setBloomBitsPerKey(int bitsPerKey)` Set the number of bits per key used by the internal bloom filter in the plain table sst format.
`PlainTableConfig`	`setEncodingType(EncodingType encodingType)` Sets the encoding type.
`PlainTableConfig`	`setFullScanMode(boolean fullScanMode)` Set full scan mode, if true the whole file will be read one record by one without using the index.
`PlainTableConfig`	`setHashTableRatio(double ratio)` hashTableRatio is the desired utilization of the hash table used for prefix hashing.
`PlainTableConfig`	`setHugePageTlbSize(int hugePageTlbSize)` huge_page_tlb_size: if ≤0, allocate hash indexes and blooms from malloc otherwise from huge page TLB.
`PlainTableConfig`	`setIndexSparseness(int sparseness)` Index sparseness determines the index interval for keys inside the same prefix.
`PlainTableConfig`	`setKeySize(int keySize)` Set the length of the user key.
`PlainTableConfig`	`setStoreIndexInFile(boolean storeIndexInFile)` If set to true: compute plain table index and bloom filter during file building and store it in file.
`boolean`	`storeIndexInFile()` Return a boolean value indicating if index shall be stored in a file.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 字段详细资料
  - VARIABLE_LENGTH
```
public static final int VARIABLE_LENGTH
```
    另请参阅:
    
    常量字段值
  - DEFAULT_BLOOM_BITS_PER_KEY
```
public static final int DEFAULT_BLOOM_BITS_PER_KEY
```
    另请参阅:
    
    常量字段值
  - DEFAULT_HASH_TABLE_RATIO
```
public static final double DEFAULT_HASH_TABLE_RATIO
```
    另请参阅:
    
    常量字段值
  - DEFAULT_INDEX_SPARSENESS
```
public static final int DEFAULT_INDEX_SPARSENESS
```
    另请参阅:
    
    常量字段值
  - DEFAULT_HUGE_TLB_SIZE
```
public static final int DEFAULT_HUGE_TLB_SIZE
```
    另请参阅:
    
    常量字段值
  - DEFAULT_ENCODING_TYPE
```
public static final EncodingType DEFAULT_ENCODING_TYPE
```
  - DEFAULT_FULL_SCAN_MODE
```
public static final boolean DEFAULT_FULL_SCAN_MODE
```
    另请参阅:
    
    常量字段值
  - DEFAULT_STORE_INDEX_IN_FILE
```
public static final boolean DEFAULT_STORE_INDEX_IN_FILE
```
    另请参阅:
    
    常量字段值
- 构造器详细资料
  - PlainTableConfig
```
public PlainTableConfig()
```
- 方法详细资料
  - setKeySize
```
public PlainTableConfig setKeySize(int keySize)
```
    Set the length of the user key. If it is set to be VARIABLE_LENGTH, then it indicates the user keys are of variable length.
    
    Otherwise,all the keys need to have the same length in byte.
    
    DEFAULT: VARIABLE_LENGTH
    
    参数:
    
    keySize - the length of the user key.
    
    返回:
    
    the reference to the current config.
  - keySize
```
public int keySize()
```
    返回:
    
    the specified size of the user key. If VARIABLE_LENGTH, then it indicates variable-length key.
  - setBloomBitsPerKey
```
public PlainTableConfig setBloomBitsPerKey(int bitsPerKey)
```
    Set the number of bits per key used by the internal bloom filter in the plain table sst format.
    
    参数:
    
    bitsPerKey - the number of bits per key for bloom filer.
    
    返回:
    
    the reference to the current config.
  - bloomBitsPerKey
```
public int bloomBitsPerKey()
```
    返回:
    
    the number of bits per key used for the bloom filter.
  - setHashTableRatio
```
public PlainTableConfig setHashTableRatio(double ratio)
```
    hashTableRatio is the desired utilization of the hash table used for prefix hashing. The ideal ratio would be the number of prefixes / the number of hash buckets. If this value is set to zero, then hash table will not be used.
    
    参数:
    
    ratio - the hash table ratio.
    
    返回:
    
    the reference to the current config.
  - hashTableRatio
```
public double hashTableRatio()
```
    返回:
    
    the hash table ratio.
  - setIndexSparseness
```
public PlainTableConfig setIndexSparseness(int sparseness)
```
    Index sparseness determines the index interval for keys inside the same prefix. This number is equal to the maximum number of linear search required after hash and binary search. If it's set to 0, then each key will be indexed.
    
    参数:
    
    sparseness - the index sparseness.
    
    返回:
    
    the reference to the current config.
  - indexSparseness
```
public long indexSparseness()
```
    返回:
    
    the index sparseness.
  - setHugePageTlbSize
```
public PlainTableConfig setHugePageTlbSize(int hugePageTlbSize)
```
    huge_page_tlb_size: if ≤0, allocate hash indexes and blooms from malloc otherwise from huge page TLB.
    
    The user needs to reserve huge pages for it to be allocated, like: sysctl -w vm.nr_hugepages=20
    
    See linux doc Documentation/vm/hugetlbpage.txt
    
    参数:
    
    hugePageTlbSize - huge page tlb size
    
    返回:
    
    the reference to the current config.
  - hugePageTlbSize
```
public int hugePageTlbSize()
```
    Returns the value for huge page tlb size
    
    返回:
    
    hugePageTlbSize
  - setEncodingType
```
public PlainTableConfig setEncodingType(EncodingType encodingType)
```
    Sets the encoding type.
    This setting determines how to encode the keys. See enum EncodingType for the choices.
    
    The value will determine how to encode keys when writing to a new SST file. This value will be stored inside the SST file which will be used when reading from the file, which makes it possible for users to choose different encoding type when reopening a DB. Files with different encoding types can co-exist in the same DB and can be read.
    
    参数:
    
    encodingType - EncodingType value.
    
    返回:
    
    the reference to the current config.
  - encodingType
```
public EncodingType encodingType()
```
    Returns the active EncodingType
    
    返回:
    
    currently set encoding type
  - setFullScanMode
```
public PlainTableConfig setFullScanMode(boolean fullScanMode)
```
    Set full scan mode, if true the whole file will be read one record by one without using the index.
    
    参数:
    
    fullScanMode - boolean value indicating if full scan mode shall be enabled.
    
    返回:
    
    the reference to the current config.
  - fullScanMode
```
public boolean fullScanMode()
```
    Return if full scan mode is active
    
    返回:
    
    boolean value indicating if the full scan mode is enabled.
  - setStoreIndexInFile
```
public PlainTableConfig setStoreIndexInFile(boolean storeIndexInFile)
```
    If set to true: compute plain table index and bloom filter during file building and store it in file. When reading file, index will be mmaped instead of doing recomputation.
    
    参数:
    
    storeIndexInFile - value indicating if index shall be stored in a file
    
    返回:
    
    the reference to the current config.
  - storeIndexInFile
```
public boolean storeIndexInFile()
```
    Return a boolean value indicating if index shall be stored in a file.
    
    返回:
    
    currently set value for store index in file.
  - newTableFactoryHandle
```
protected long newTableFactoryHandle()
```
    从类复制的说明: TableFormatConfig
    
    This function should only be called by Options.setTableFormatConfig(), which will create a c++ shared-pointer to the c++ TableFactory that associated with the Java TableFormatConfig.
    
    指定者:
    
    newTableFactoryHandle 在类中 TableFormatConfig
    
    返回:
    
    native handle address to native table instance.

类 PlainTableConfig

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

VARIABLE_LENGTH

DEFAULT_BLOOM_BITS_PER_KEY

DEFAULT_HASH_TABLE_RATIO

DEFAULT_INDEX_SPARSENESS

DEFAULT_HUGE_TLB_SIZE

DEFAULT_ENCODING_TYPE

DEFAULT_FULL_SCAN_MODE

DEFAULT_STORE_INDEX_IN_FILE

构造器详细资料

PlainTableConfig

方法详细资料

setKeySize

keySize

setBloomBitsPerKey

bloomBitsPerKey

setHashTableRatio

hashTableRatio

setIndexSparseness

indexSparseness

setHugePageTlbSize

hugePageTlbSize

setEncodingType

encodingType

setFullScanMode

fullScanMode

setStoreIndexInFile

storeIndexInFile

newTableFactoryHandle