[jira] [Updated] (FLINK-28838) Avoid to notify the elementQueue consumer when the fetch result is empty

["Xintong Song (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-28838?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Xintong Song updated FLINK-28838:
---------------------------------
    Fix Version/s: 1.18.0
                       (was: 1.17.0)

> Avoid to notify the elementQueue consumer when the fetch result is empty
> ------------------------------------------------------------------------
>
>                 Key: FLINK-28838
>                 URL: https://issues.apache.org/jira/browse/FLINK-28838
>             Project: Flink
>          Issue Type: Improvement
>          Components: Connectors / Common
>    Affects Versions: 1.15.0, 1.15.1
>            Reporter: Aitozi
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.18.0
>
>         Attachments: 20220805165441.jpg
>
>
> When using the new source api, I found that if the source has no data, it still brings high cpu usage. 
> The reason behind this is that it will always return the {{RecordsWithSplitIds}} from the {{splitReader.fetch}} in FetchTask and it will be added to the elementQueue. It will make the consumer be notified to wake up frequently.
> This causes the thread to keep busy to run and wake up, which leads to the high sys and user cpu usage.
> I think not all the SplitReader#fetch will block until there is data, if it returns immediately when there is no data, then this problem will happen



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