Implementation:Apache Flink AsyncSinkConnectorOptions

Knowledge Sources	Apache_Flink
Domains	Connectors, Table_API
Last Updated	2026-02-09 00:00 GMT

Overview

A configuration options class defining the optional Table API/SQL properties for async sink connectors.

Description

AsyncSinkConnectorOptions is a class in the flink-connector-base module that defines the standard ConfigOption constants for configuring AsyncSinkBase behavior through Flink's Table API/SQL. Each option corresponds to a tuning parameter of the async sink framework and is declared as a public static final ConfigOption. All options have no default values, meaning they are entirely optional and will fall back to the AsyncSinkBase defaults if not specified.

The five configuration options defined are: MAX_BATCH_SIZE (sink.batch.max-size), MAX_IN_FLIGHT_REQUESTS (sink.requests.max-inflight), MAX_BUFFERED_REQUESTS (sink.requests.max-buffered), FLUSH_BUFFER_SIZE (sink.flush-buffer.size), and FLUSH_BUFFER_TIMEOUT (sink.flush-buffer.timeout). These options are registered as optional table options by AsyncDynamicTableSinkFactory.

Usage

Connector developers reference these options when building Table API/SQL connectors backed by AsyncSinkBase. The options are automatically included in the optional options set by AsyncDynamicTableSinkFactory. End users specify these options in SQL DDL statements or Table API configurations to tune async sink performance.

Code Reference

Source Location

Repository: Apache_Flink
File: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/table/AsyncSinkConnectorOptions.java
Lines: 1-67

Signature

@PublicEvolving
public class AsyncSinkConnectorOptions

Import

import org.apache.flink.connector.base.table.AsyncSinkConnectorOptions;

I/O Contract

Inputs

Name	Type	Required	Description
(none)			This class has no inputs; it only declares static configuration option constants.

Outputs

Name	Type	Description
MAX_BATCH_SIZE	ConfigOption<Integer>	sink.batch.max-size - Maximum number of elements that may be passed in a batch to be written downstream. No default.
MAX_IN_FLIGHT_REQUESTS	ConfigOption<Integer>	sink.requests.max-inflight - Request threshold for uncompleted requests before blocking new write requests. No default.
MAX_BUFFERED_REQUESTS	ConfigOption<Integer>	sink.requests.max-buffered - Maximum number of buffered records before applying backpressure. No default.
FLUSH_BUFFER_SIZE	ConfigOption<Long>	sink.flush-buffer.size - Threshold value in bytes for writer buffer flushing. No default.
FLUSH_BUFFER_TIMEOUT	ConfigOption<Long>	sink.flush-buffer.timeout - Threshold time in milliseconds for an element to be in a buffer before being flushed. No default.

Configuration Reference

SQL Key	Java Constant	Type	Default	Description
sink.batch.max-size	MAX_BATCH_SIZE	Integer	(none)	Maximum number of elements per batch write.
sink.requests.max-inflight	MAX_IN_FLIGHT_REQUESTS	Integer	(none)	Maximum uncompleted write requests before blocking.
sink.requests.max-buffered	MAX_BUFFERED_REQUESTS	Integer	(none)	Maximum buffered records before applying backpressure.
sink.flush-buffer.size	FLUSH_BUFFER_SIZE	Long	(none)	Buffer size threshold in bytes for flushing.
sink.flush-buffer.timeout	FLUSH_BUFFER_TIMEOUT	Long	(none)	Maximum time in milliseconds before buffer is flushed.

Usage Examples

// Using async sink options in a SQL DDL statement
// CREATE TABLE my_sink (
//   id BIGINT,
//   name STRING
// ) WITH (
//   'connector' = 'my-async-sink',
//   'format' = 'json',
//   'sink.batch.max-size' = '500',
//   'sink.requests.max-inflight' = '10',
//   'sink.requests.max-buffered' = '1000',
//   'sink.flush-buffer.size' = '5242880',
//   'sink.flush-buffer.timeout' = '5000'
// );

// Referencing options programmatically in a factory
ReadableConfig tableOptions = helper.getOptions();
Optional<Integer> maxBatchSize = tableOptions.getOptional(AsyncSinkConnectorOptions.MAX_BATCH_SIZE);
Optional<Long> flushBufferSize = tableOptions.getOptional(AsyncSinkConnectorOptions.FLUSH_BUFFER_SIZE);
Optional<Long> flushTimeout = tableOptions.getOptional(AsyncSinkConnectorOptions.FLUSH_BUFFER_TIMEOUT);

Related Pages

Principle:Apache_Flink_Async_Sink_Framework
Apache_Flink_AsyncDynamicTableSinkFactory - Factory that registers these options as optional table options
Apache_Flink_AsyncDynamicTableSink - Table sink configured by these options
Apache_Flink_AsyncDynamicTableSinkBuilder - Builder that accepts these option values

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