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Aitozi edited comment on FLINK-28838 at 8/20/22 10:35 AM: ---------------------------------------------------------- Hi [~renqs] do you have any further comments? If no objection, I'd like to open a PR for this. was (Author: aitozi): Hi [~renqs] do you have any further comments, If no objection, I'd like to open a PR for this ? > 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 > Fix For: 1.16.0 > > 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)