[jira] [Commented] (FLINK-5917) Remove MapState.size()

["Aljoscha Krettek (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-5917?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15884131#comment-15884131 ] 

Aljoscha Krettek commented on FLINK-5917:
-----------------------------------------

[~srichter] and [~xiaogang.shi], what do you think about this?

> Remove MapState.size()
> ----------------------
>
>                 Key: FLINK-5917
>                 URL: https://issues.apache.org/jira/browse/FLINK-5917
>             Project: Flink
>          Issue Type: Improvement
>          Components: DataStream API
>    Affects Versions: 1.3.0
>            Reporter: Aljoscha Krettek
>
> I'm proposing to remove {{size()}} because it is a prohibitively expensive operation and users might not be aware of it. Instead of {{size()}} users can use an iterator over all mappings to determine the size, when doing this they will be aware of the fact that it is a costly operation.
> Right now, {{size()}} is only costly on the RocksDB state backend but I think with future developments on the in-memory state backend it might also become an expensive operation there.



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