org.rocksdb

Enum IndexType

java.lang.Object

java.lang.Enum<IndexType>

org.rocksdb.IndexType

All Implemented Interfaces:

Serializable, Comparable<IndexType>

public enum IndexType
extends Enum<IndexType>

IndexType used in conjunction with BlockBasedTable.

Enum Constant Summary

Enum Constants

Enum Constant and Description
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.

Method Summary

Modifier and Type	Method and Description
byte	getValue() Returns the byte value of the enumerations value
static IndexType	valueOf(String name) Returns the enum constant of this type with the specified name.
static IndexType[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

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

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

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.

Method Detail

values

public static IndexType[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

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

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static IndexType valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

getValue

public byte getValue()

Returns the byte value of the enumerations value

Returns:

byte representation