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Posted to user@flink.apache.org by "ravi_suryavanshi.yahoo.com via user" <us...@flink.apache.org> on 2025/11/19 05:31:19 UTC

Apache Kafka SQL Connector: Scan Source: bounded support?

Hi,We are currently evaluating the Apache Kafka SQL Connector. According to the Flink v2.0.1 documentation, a Kafka Scan Source can be used as an unbounded source. However, we also noticed the scan.bounded.mode option, and when this option is enabled, the Flink job runs in batch mode.
We would like to confirm whether batch mode is officially supported for the Kafka SQL Connector. If it is supported, what behavior should we expect when using the different bounded modes: latest-offset, group-offsets, timestamp, and specific-offsets?
In our tests, latest-offset returns old events, while timestamp returns no events.
Regards,Ravi

Re: Apache Kafka SQL Connector: Scan Source: bounded support?

Posted by Yaroslav Tkachenko <ya...@sap1ens.com>.

Hi Ravi,

The official Flink documentation has a pretty good explanation for this:
https://nightlies.apache.org/flink/flink-docs-release-2.2/docs/connectors/table/kafka/#bounded-ending-position

And yes, I can confirm it's officially supported. The behaviour also
depends on your start reading position ("scan.startup.mode"), you need to
specify both.

On Thu, Jan 22, 2026 at 6:14 AM ravi_suryavanshi.yahoo.com via user <
user@flink.apache.org> wrote:

> Hi,
> Does anyone have input/info regarding this?
> Regards,
> Ravi
>
> On Wednesday, 19 November 2025 at 11:04:08 am IST,
> ravi_suryavanshi.yahoo.com via user <us...@flink.apache.org> wrote:
>
>
> Hi,
> We are currently evaluating the Apache Kafka SQL Connector. According to
> the Flink v2.0.1 documentation, a Kafka Scan Source can be used as an
> unbounded source. However, we also noticed the scan.bounded.mode option,
> and when this option is enabled, the Flink job runs in batch mode.
>
> We would like to confirm whether batch mode is officially supported for
> the Kafka SQL Connector. If it is supported, what behavior should we expect
> when using the different bounded modes: latest-offset, group-offsets,
> timestamp, and specific-offsets?
>
> In our tests, latest-offset returns old events, while timestamp returns no
> events.
>
> Regards,
> Ravi
>
>

Re: Apache Kafka SQL Connector: Scan Source: bounded support?

Posted by "ravi_suryavanshi.yahoo.com via user" <us...@flink.apache.org>.

 Hi,Does anyone have input/info regarding this?Regards,Ravi
    On Wednesday, 19 November 2025 at 11:04:08 am IST, ravi_suryavanshi.yahoo.com via user <us...@flink.apache.org> wrote:  
 
 Hi,We are currently evaluating the Apache Kafka SQL Connector. According to the Flink v2.0.1 documentation, a Kafka Scan Source can be used as an unbounded source. However, we also noticed the scan.bounded.mode option, and when this option is enabled, the Flink job runs in batch mode.
We would like to confirm whether batch mode is officially supported for the Kafka SQL Connector. If it is supported, what behavior should we expect when using the different bounded modes: latest-offset, group-offsets, timestamp, and specific-offsets?
In our tests, latest-offset returns old events, while timestamp returns no events.
Regards,Ravi