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https://issues.apache.org/jira/browse/FLINK-5655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15946719#comment-15946719
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ASF GitHub Bot commented on FLINK-5655:
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Github user fhueske commented on the issue:
https://github.com/apache/flink/pull/3629
The problem with the state clean-up is that we always keep some state for
each key. If the keys of the stream are moving (i.e., there is not a fixed set
of keys) then the size of the state will grow infinitely.
So we should add a configuration option that defines when the state of a
key can be cleaned, i.e., a min and max duration how long we keep the state of
a key without any updates. This should be similar to the RocksDB TTL, but I
would like to have this not only for RocksDB but for all backends by
registering timers that clear the state.
I don't think we have to add this for this PR but should address this issue
before the 1.3 release.
> Add event time OVER RANGE BETWEEN x PRECEDING aggregation to SQL
> ----------------------------------------------------------------
>
> Key: FLINK-5655
> URL: https://issues.apache.org/jira/browse/FLINK-5655
> Project: Flink
> Issue Type: Sub-task
> Components: Table API & SQL
> Reporter: Fabian Hueske
> Assignee: sunjincheng
>
> The goal of this issue is to add support for OVER RANGE aggregations on event
> time streams to the SQL interface.
> Queries similar to the following should be supported:
> {code}
> SELECT
> a,
> SUM(b) OVER (PARTITION BY c ORDER BY rowTime() RANGE BETWEEN INTERVAL '1'
> HOUR PRECEDING AND CURRENT ROW) AS sumB,
> MIN(b) OVER (PARTITION BY c ORDER BY rowTime() RANGE BETWEEN INTERVAL '1'
> HOUR PRECEDING AND CURRENT ROW) AS minB
> FROM myStream
> {code}
> The following restrictions should initially apply:
> - All OVER clauses in the same SELECT clause must be exactly the same.
> - The PARTITION BY clause is optional (no partitioning results in single
> threaded execution).
> - The ORDER BY clause may only have rowTime() as parameter. rowTime() is a
> parameterless scalar function that just indicates processing time mode.
> - UNBOUNDED PRECEDING is not supported (see FLINK-5658)
> - FOLLOWING is not supported.
> The restrictions will be resolved in follow up issues. If we find that some
> of the restrictions are trivial to address, we can add the functionality in
> this issue as well.
> This issue includes:
> - Design of the DataStream operator to compute OVER ROW aggregates
> - Translation from Calcite's RelNode representation (LogicalProject with
> RexOver expression).
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