Implementation:Apache Flink CompactorRequest Construction

Knowledge Sources	Apache Flink
Domains	Stream_Processing, File_IO
Last Updated	2026-02-09 00:00 GMT

Overview

Concrete tool for encapsulating per-bucket file lists into serializable compaction requests provided by the Apache Flink connector-files module.

Description

CompactorRequest is a simple Serializable container with a bucket ID and two lists of FileSinkCommittable: files to compact and files to pass through unchanged. CompactorRequestSerializer handles serialization using a magic number (0x2fc61e19) for validation and delegates to FileSinkCommittableSerializer for individual committable serialization.

Usage

This is an internal data class used as the transfer format between the CompactCoordinator and CompactorOperator.

Code Reference

Source Location

• Repository: Apache Flink
• File: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/sink/compactor/operator/CompactorRequest.java
• Lines: L33-73

Signature

@Internal
public class CompactorRequest implements Serializable {

    public CompactorRequest(String bucketId);

    public CompactorRequest(
            String bucketId,
            List<FileSinkCommittable> committableToCompact,
            List<FileSinkCommittable> committableToPassthrough);

    public void addToCompact(FileSinkCommittable committable);
    public void addToPassthrough(FileSinkCommittable committable);
    public String getBucketId();
    public List<FileSinkCommittable> getCommittableToCompact();
    public List<FileSinkCommittable> getCommittableToPassthrough();
}

Import

import org.apache.flink.connector.file.sink.compactor.operator.CompactorRequest;
// Internal class

I/O Contract

Inputs

Name	Type	Required	Description
bucketId	String	Yes	Bucket being compacted
committableToCompact	List<FileSinkCommittable>	Yes	Files to merge
committableToPassthrough	List<FileSinkCommittable>	No	Files to forward unchanged

Outputs

Name	Type	Description
request	CompactorRequest	Serializable request for the compactor operator

Usage Examples

Request Creation

// Created by CompactCoordinator when trigger fires:
CompactorRequest request = new CompactorRequest("2024/01/15/14");
request.addToCompact(pendingFile1);
request.addToCompact(pendingFile2);
request.addToPassthrough(cleanupCommittable);
// Emitted downstream to CompactorOperator

Related Pages

Implements Principle

• Principle:Apache_Flink_Compaction_Request_Triggering