[jira] [Created] (FLINK-39382) [Docs][Kafka] Clarify properties.auto.offset.reset support in SQL connector

["Kumar Mallikarjuna (Jira)" <ji...@apache.org>]

Kumar Mallikarjuna created FLINK-39382:
------------------------------------------

             Summary: [Docs][Kafka] Clarify properties.auto.offset.reset support in SQL connector
                 Key: FLINK-39382
                 URL: https://issues.apache.org/jira/browse/FLINK-39382
             Project: Flink
          Issue Type: Improvement
          Components: Connectors / Kafka
            Reporter: Kumar Mallikarjuna


The current documentation for the Flink SQL Kafka Connector contains a misleading statement regarding the {{auto.offset.reset}} property that contradicts the actual behavior of the connector since Flink 1.15 (specifically, the resolution of FLINK-24697).

*Current Documentation Statement:* On the [Kafka SQL Connector page|https://nightlies.apache.org/flink/flink-docs-stable/docs/connectors/table/kafka/], the docs state:
{quote}_"But there are some configurations that do not support to set, because Flink will override them, e.g. 'auto.offset.reset'."_
{quote}
 

While it is true that Flink overrides the underlying Kafka Consumer client's {{auto.offset.reset}} property to {{none}} (to protect its own state management), the statement implies that setting {{properties.auto.offset.reset}} in the Flink DDL is useless or entirely unsupported.

Because of the fix introduced in FLINK-24697, this is no longer accurate. When a user configures {{{}scan.startup.mode = 'group-offsets'{}}}, the Flink SQL connector explicitly parses {{properties.auto.offset.reset}} from the DDL to act as the fallback initialization strategy when no committed offsets are found for the consumer group.

 

https://github.com/apache/flink-connector-kafka/blob/bd2fd2b2c8a48b7d2a05387fc4fda61e878c902f/flink-connector-kafka/src/main/java/org/apache/flink/streaming/connectors/kafka/table/KafkaDynamicSource.java#L453-L456



--
This message was sent by Atlassian Jira
(v8.20.10#820010)