[FLINK-29854] Make Record Size Flush Strategy Optional for Async Sink

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Connectors / Common
• Assignee: Ahmed Hamdy
• Reporter: Danny Cranmer
• Created: 02/Nov/22 19:41
• Updated: 03/Jan/23 12:43

Description

Background

Currently AsyncSinkWriter supports three mechanisms that trigger a flush to the destination:

• TIme based 
• Batch size in bytes
• Number of records in the batch

For "batch size in bytes" one must implement getSizeInBytes in order for the base to calculate the total batch size. In some cases computing the batch size within the AsyncSinkWriter is an expensive operation, or not possible. For example, the DynamoDB connector needs to determine the serialized size of DynamoDbWriteRequest. (https://github.com/apache/flink-connector-dynamodb/pull/1/files#r1012223894)

Scope

Add a feature to make "size in bytes" support optional, this includes:

• Connectors will not be required to implement getSizeInBytes
• Batches will not be validated for max size
• Records will not be validated for size
• Batches are not flushed when max size is exceeded

The sink implementer can decide if it is appropriate to enable this feature.