[
https://issues.apache.org/jira/browse/FLINK-16528?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17432433#comment-17432433
]
jocean.shi commented on FLINK-16528:
------------------------------------
Hi [~jark] , What is the semantics In cdc scene, 10 records(mybe those are the
update of one data ) or 10 data?
> Support Limit push down for Kafka streaming sources
> ---------------------------------------------------
>
> Key: FLINK-16528
> URL: https://issues.apache.org/jira/browse/FLINK-16528
> Project: Flink
> Issue Type: New Feature
> Components: Table SQL / Ecosystem
> Reporter: Jark Wu
> Priority: Minor
> Labels: auto-deprioritized-major, usability
>
> Currently, a limit query {{SELECT * FROM kafka LIMIT 10}} will be translated
> into TopN operator and will scan the full data in the source. However,
> {{LIMIT}} is a very useful feature in SQL CLI to explore data in the source.
> It doesn't make sense it never stop.
> We can support such case in streaming mode (ignore the text format):
> {code}
> flink > SELECT * FROM kafka LIMIT 10;
> kafka_key | user_name | lang | created_at
> --------------------+-----------------+------+-------------------------
> 494227746231685121 | burncaniff | en | 2014-07-29 14:07:31.000
> 494227746214535169 | gu8tn | ja | 2014-07-29 14:07:31.000
> 494227746219126785 | pequitamedicen | es | 2014-07-29 14:07:31.000
> 494227746201931777 | josnyS | ht | 2014-07-29 14:07:31.000
> 494227746219110401 | Cafe510 | en | 2014-07-29 14:07:31.000
> 494227746210332673 | Da_JuanAnd_Only | en | 2014-07-29 14:07:31.000
> 494227746193956865 | Smile_Kidrauhl6 | pt | 2014-07-29 14:07:31.000
> 494227750426017793 | CashforeverCD | en | 2014-07-29 14:07:32.000
> 494227750396653569 | FilmArsivimiz | tr | 2014-07-29 14:07:32.000
> 494227750388256769 | jmolas | es | 2014-07-29 14:07:32.000
> (10 rows)
> {code}
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
