Module org.elasticsearch.server

Package org.elasticsearch.common

Class TimeBasedKOrderedUUIDGenerator

java.lang.Object

org.elasticsearch.common.TimeBasedKOrderedUUIDGenerator

public class TimeBasedKOrderedUUIDGenerator
extends Object

Generates a base64-encoded, k-ordered UUID string optimized for compression and efficient indexing.

This method produces a time-based UUID where slowly changing components like the timestamp appear first, improving prefix-sharing and compression during indexing. It ensures uniqueness across nodes by incorporating a timestamp, a MAC address, and a sequence ID.

Timestamp: Represents the current time in milliseconds, ensuring ordering and uniqueness.
MAC Address: Ensures uniqueness across different coordinators.
Sequence ID: Differentiates UUIDs generated within the same millisecond, ensuring uniqueness even at high throughput.

The result is a compact base64-encoded string, optimized for efficient compression of the _id field in an inverted index.

Field Summary

Fields

Modifier and Type	Field	Description
protected final AtomicLong	lastTimestamp
protected final AtomicInteger	sequenceNumber
protected final Supplier<Long>	timestampSupplier

Constructor Summary

Constructors

Constructor	Description
TimeBasedKOrderedUUIDGenerator(Supplier<Long> timestampSupplier, Supplier<Integer> sequenceIdSupplier, Supplier<byte[]> macAddressSupplier)

Method Summary

Modifier and Type	Method	Description
String	getBase64UUID()
String	getBase64UUID(OptionalInt hash)
protected byte[]	macAddress()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

sequenceNumber

protected final AtomicInteger sequenceNumber

lastTimestamp

protected final AtomicLong lastTimestamp

timestampSupplier

protected final Supplier<Long> timestampSupplier

Constructor Details

TimeBasedKOrderedUUIDGenerator

public TimeBasedKOrderedUUIDGenerator(Supplier<Long> timestampSupplier,
 Supplier<Integer> sequenceIdSupplier,
 Supplier<byte[]> macAddressSupplier)

Method Details

getBase64UUID

public String getBase64UUID()

getBase64UUID

public String getBase64UUID(OptionalInt hash)

macAddress

protected byte[] macAddress()