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https://issues.apache.org/jira/browse/FLINK-3779?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15413647#comment-15413647
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ASF GitHub Bot commented on FLINK-3779:
---------------------------------------

Github user asfgit closed the pull request at:

    https://github.com/apache/flink/pull/2051


> Add support for queryable state
> -------------------------------
>
>                 Key: FLINK-3779
>                 URL: https://issues.apache.org/jira/browse/FLINK-3779
>             Project: Flink
>          Issue Type: Improvement
>          Components: Distributed Coordination
>            Reporter: Ufuk Celebi
>            Assignee: Ufuk Celebi
>
> Flink offers state abstractions for user functions in order to guarantee 
> fault-tolerant processing of streams. Users can work with both 
> non-partitioned (Checkpointed interface) and partitioned state 
> (getRuntimeContext().getState(ValueStateDescriptor) and other variants).
> The partitioned state interface provides access to different types of state 
> that are all scoped to the key of the current input element. This type of 
> state can only be used on a KeyedStream, which is created via stream.keyBy().
> Currently, all of this state is internal to Flink and used in order to 
> provide processing guarantees in failure cases (e.g. exactly-once processing).
> The goal of Queryable State is to expose this state outside of Flink by 
> supporting queries against the partitioned key value state.
> This will help to eliminate the need for distributed operations/transactions 
> with external systems such as key-value stores which are often the bottleneck 
> in practice. Exposing the local state to the outside moves a good part of the 
> database work into the stream processor, allowing both high throughput 
> queries and immediate access to the computed state.
> This is the initial design doc for the feature: 
> https://docs.google.com/document/d/1NkQuhIKYmcprIU5Vjp04db1HgmYSsZtCMxgDi_iTN-g.
>  Feel free to comment.



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