Package org.apache.flink.cdc.common.pipeline

Enum HashFunctionStrategy

java.lang.Object

java.lang.Enum<HashFunctionStrategy>

org.apache.flink.cdc.common.pipeline.HashFunctionStrategy

All Implemented Interfaces:

Serializable, Comparable<HashFunctionStrategy>

@PublicEvolving
public enum HashFunctionStrategy
extends Enum<HashFunctionStrategy>

Partitioning strategy for DataChangeEvent in Flink CDC pipeline.

This enum defines different strategies used by PrePartitionOperator to determine which downstream subtask an event should be routed to.

Enum Constant Summary

Enum Constants

Enum Constant	Description
PRIMARY_KEY	Hash by TableId and primary keys.
SINK_DEFINED	Use the HashFunctionProvider defined by the sink.
TABLE_ID	Hash by TableId only.

Method Summary

Modifier and Type	Method	Description
static HashFunctionStrategy	valueOf(String name)	Returns the enum constant of this type with the specified name.
static HashFunctionStrategy[]	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

SINK_DEFINED

public static final HashFunctionStrategy SINK_DEFINED

Use the HashFunctionProvider defined by the sink.

This is the default behavior when sink.partitioning.strategy is not explicitly set. The provider returned by the sink's getDataChangeEventHashFunctionProvider method will be used, preserving backward compatibility with existing pipeline configurations.

This is the only supported strategy for sinks that require sink-defined routing, such as paimon, fluss, and maxcompute.

PRIMARY_KEY

public static final HashFunctionStrategy PRIMARY_KEY

Hash by TableId and primary keys.

This strategy computes hash based on TableId (namespace, schema, table) combined with primary key column values. Events with the same TableId and primary key will be routed to the same subtask, while events from the same table with different primary keys may be spread across multiple subtasks for load balancing.

This is suitable when you want good distribution of data across subtasks and don't require strict ordering within a table.

This strategy is not supported for paimon, fluss, or maxcompute sinks.

TABLE_ID

public static final HashFunctionStrategy TABLE_ID

Hash by TableId only.

This strategy computes hash based solely on TableId (namespace, schema, table), ignoring the record payload entirely. All events from the same table will be routed to the same subtask, ensuring per-table ordering semantics.

This is suitable when:

• The sink requires strict single-writer-per-table semantics.
• The table has no primary key or has a changing primary key set.
• You want to avoid cross-subtask reordering within the same table.

This strategy is not supported for paimon, fluss, or maxcompute sinks.

Method Detail

values

public static HashFunctionStrategy[] 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 (HashFunctionStrategy c : HashFunctionStrategy.values())
    System.out.println(c);

Returns:

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

valueOf

public static HashFunctionStrategy 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