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https://issues.apache.org/jira/browse/APEXMALHAR-2244?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15513770#comment-15513770
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Siyuan Hua commented on APEXMALHAR-2244:
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Each spillable DS implementation use a SpillableStateStore to store things and
we can make ManagedTimeUnifiedStateImpl implement the store as well and it can
take some time extract function to get/calculate time and time buckets from
each V/KV data. And the Store can be setup by the WindowedOperator, correct?
> Optimize WindowedStorage and Spillable data structures for time series
> ----------------------------------------------------------------------
>
> Key: APEXMALHAR-2244
> URL: https://issues.apache.org/jira/browse/APEXMALHAR-2244
> Project: Apache Apex Malhar
> Issue Type: Sub-task
> Reporter: David Yan
> Assignee: Siyuan Hua
>
> The spillable data structures currently does not make any assumption about
> the key that is used in Managed State, and as a result, it uses
> ManagedStateImpl to interface with Managed State and uses time buckets that
> are based on the apex window id. But for WindowedStorage used by
> WindowedOperator, the key to the storage is a window, which is event time
> based. Using the default ManagedStateImpl would be very inefficient for event
> time based keys, since it would write data that would belong to the same
> window to different time buckets.
> On a high level, the below summarizes roughly what needs to be done:
> 1. a way to tell the spillable data structures to use the
> ManagedTimeUnifiedStateImpl
> 2. a way to tell the spillable data structures how to extract the timestamp
> from the key. Note that in the case of WindowedOperator, the timestamp should
> be the end timestamp of the window (beginTimeMillis + durationMillis), not
> the begin timestamp.
> 3. a way to tell the spillable data structures how to assign the time bucket
> given that timestamp
> 4. with point 3, the spillable implementations of WindowedStorage will need
> to take a config parameter that says how much time (in millis) is each time
> bucket
> 5. only purge a time bucket when all keys that belong to that time bucket are
> removed and the apex window id of the first window in which the keys are all
> removed has been committed
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