org.rocksdb

枚举 IndexType

java.lang.Object

java.lang.Enum<IndexType>

org.rocksdb.IndexType

所有已实现的接口:

java.io.Serializable, java.lang.Comparable<IndexType>

public enum IndexType
extends java.lang.Enum<IndexType>

IndexType used in conjunction with BlockBasedTable.

枚举常量概要

枚举常量

枚举常量和说明
kBinarySearch A space efficient index block that is optimized for binary-search-based index.
kBinarySearchWithFirstKey Like kBinarySearch, but index also contains first key of each block.
kHashSearch The hash index, if enabled, will do the hash lookup when Options.prefix_extractor is provided.
kTwoLevelIndexSearch A two-level index implementation.

方法概要

限定符和类型	方法和说明
byte	getValue() Returns the byte value of the enumerations value
static IndexType	valueOf(java.lang.String name) 返回带有指定名称的该类型的枚举常量。
static IndexType[]	values() 按照声明该枚举类型的常量的顺序, 返回 包含这些常量的数组。

从类继承的方法 java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

从类继承的方法 java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

枚举常量详细资料

kBinarySearch

public static final IndexType kBinarySearch

A space efficient index block that is optimized for binary-search-based index.

kHashSearch

public static final IndexType kHashSearch

The hash index, if enabled, will do the hash lookup when Options.prefix_extractor is provided.

kTwoLevelIndexSearch

public static final IndexType kTwoLevelIndexSearch

A two-level index implementation. Both levels are binary search indexes.

kBinarySearchWithFirstKey

public static final IndexType kBinarySearchWithFirstKey

Like kBinarySearch, but index also contains first key of each block. This allows iterators to defer reading the block until it's actually needed. May significantly reduce read amplification of short range scans. Without it, iterator seek usually reads one block from each level-0 file and from each level, which may be expensive. Works best in combination with: - IndexShorteningMode::kNoShortening, - custom FlushBlockPolicy to cut blocks at some meaningful boundaries, e.g. when prefix changes. Makes the index significantly bigger (2x or more), especially when keys are long.

方法详细资料

values

public static IndexType[] values()

按照声明该枚举类型的常量的顺序, 返回 包含这些常量的数组。该方法可用于迭代 常量, 如下所示:

for (IndexType c : IndexType.values())
    System.out.println(c);

返回:

按照声明该枚举类型的常量的顺序返回的包含这些常量的数组

valueOf

public static IndexType valueOf(java.lang.String name)

返回带有指定名称的该类型的枚举常量。 字符串必须与用于声明该类型的枚举常量的 标识符完全匹配。(不允许有多余 的空格字符。)

参数:

name - 要返回的枚举常量的名称。

返回:

返回带有指定名称的枚举常量

抛出:

java.lang.IllegalArgumentException - 如果该枚举类型没有带有指定名称的常量

java.lang.NullPointerException - 如果参数为空值

getValue

public byte getValue()

Returns the byte value of the enumerations value

返回:

byte representation