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https://issues.apache.org/jira/browse/FLINK-19592?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

ASF GitHub Bot updated FLINK-19592:
-----------------------------------
    Labels: pull-request-available  (was: )

> MiniBatchGroupAggFunction should emit messages to prevent too early state 
> eviction of downstream operators
> ----------------------------------------------------------------------------------------------------------
>
>                 Key: FLINK-19592
>                 URL: https://issues.apache.org/jira/browse/FLINK-19592
>             Project: Flink
>          Issue Type: Bug
>          Components: Table SQL / Runtime
>    Affects Versions: 1.12.0
>            Reporter: Smile
>            Assignee: Smile
>            Priority: Minor
>              Labels: pull-request-available
>
> Currently, 
> [GroupAggFunction|https://github.com/apache/flink/blob/master/flink-table/flink-table-runtime-blink/src/main/java/org/apache/flink/table/runtime/operators/aggregate/GroupAggFunction.java#L183]
>  will emit a retract and a new insert message when a new message with the 
> same key arrives. According to 
> [Flink-8566|https://issues.apache.org/jira/browse/FLINK-8566], it's a feature 
> to prevent too early state eviction of downstream operators.
> However, 
> [MiniBatchGroupAggFunction|https://github.com/apache/flink/blob/master/flink-table/flink-table-runtime-blink/src/main/java/org/apache/flink/table/runtime/operators/aggregate/MiniBatchGroupAggFunction.java#L206]
>  doesn't. Before 
> [Flink-8566|https://issues.apache.org/jira/browse/FLINK-8566] being resolved, 
> it should also emit these messages.
> *GroupAggFunction.java:*
> {code:java}
> if (!stateCleaningEnabled && equaliser.equals(prevAggValue, newAggValue)) {
>       // newRow is the same as before and state cleaning is not enabled.
>       // We do not emit retraction and acc message.
>       // If state cleaning is enabled, we have to emit messages to prevent 
> too early
>       // state eviction of downstream operators.
>       return;
> } else {
>       // retract previous result
>       if (generateUpdateBefore) {
>               // prepare UPDATE_BEFORE message for previous row
>               resultRow.replace(currentKey, 
> prevAggValue).setRowKind(RowKind.UPDATE_BEFORE);
>               out.collect(resultRow);
>       }
>       // prepare UPDATE_AFTER message for new row
>       resultRow.replace(currentKey, 
> newAggValue).setRowKind(RowKind.UPDATE_AFTER);
> }
> {code}
> *MiniBatchGroupAggFunction.java:*
>  
> {code:java}
> if (!equaliser.equals(prevAggValue, newAggValue)) {
>       // new row is not same with prev row
>       if (generateUpdateBefore) {
>               // prepare UPDATE_BEFORE message for previous row
>               resultRow.replace(currentKey, 
> prevAggValue).setRowKind(RowKind.UPDATE_BEFORE);
>               out.collect(resultRow);
>       }
>       // prepare UPDATE_AFTER message for new row
>       resultRow.replace(currentKey, 
> newAggValue).setRowKind(RowKind.UPDATE_AFTER);
>       out.collect(resultRow);
> }
> // new row is same with prev row, no need to output
> {code}
>  
>  
>  
>  



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