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https://issues.apache.org/jira/browse/FLINK-24597?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17436629#comment-17436629
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Yue Ma commented on FLINK-24597:
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[~roman] So, can this ticket be assigned to me ?
> RocksdbStateBackend getKeysAndNamespaces would return duplicate data when
> using MapState
> -----------------------------------------------------------------------------------------
>
> Key: FLINK-24597
> URL: https://issues.apache.org/jira/browse/FLINK-24597
> Project: Flink
> Issue Type: Bug
> Components: API / State Processor, Runtime / State Backends
> Affects Versions: 1.14.0, 1.12.4, 1.13.3
> Reporter: Yue Ma
> Priority: Major
> Labels: pull-request-available
> Attachments: image-2021-11-01-14-19-58-372.png
>
>
> For example, in RocksdbStateBackend , if we worked in VoidNamespace , and And
> use the ValueState like below .
> {code:java}
> // insert record
> for (int i = 0; i < 3; ++i) {
> keyedStateBackend.setCurrentKey(i);
> testValueState.update(String.valueOf(i));
> }
> {code}
> Then we get all the keysAndNamespace according the method
> RocksDBKeyedStateBackend#getKeysAndNamespaces().The result of the traversal is
> <1,VoidNamespace>,<2,VoidNamespace>,<3,VoidNamespace> ,which is as expected.
> Thus，if we use MapState , and update the MapState with different user key,
> the getKeysAndNamespaces would return duplicate data with same
> keyAndNamespace.
> {code:java}
> // insert record
> for (int i = 0; i < 3; ++i) {
> keyedStateBackend.setCurrentKey(i);
> mapState.put("userKeyA_" + i, "userValue");
> mapState.put("userKeyB_" + i, "userValue");
> }
> {code}
> The result of the traversal is
>
> <1,VoidNamespace>,<1,VoidNamespace>,<2,VoidNamespace>,<2,VoidNamespace>,<3,VoidNamespace>,<3,VoidNamespace>.
> By reading the code, I found that the main reason for this problem is in the
> implementation of _RocksStateKeysAndNamespaceIterator_.
> In the _hasNext_ method, when a new keyAndNamespace is created, there is no
> comparison with the previousKeyAndNamespace. So we can refer to
> RocksStateKeysIterator to implement the same logic should solve this problem.
>
>
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