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https://issues.apache.org/jira/browse/FALCON-1406?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15685433#comment-15685433
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Srikanth Sundarrajan commented on FALCON-1406:
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HI [~ajayyadava], I have been behind this feature for nearly 3 years now. That
we go back in time to reprocess data regularly is given. There are numerous
scenarios when this may happen. The most common / frequent one being bug in
newly deployed code or un-handled data issues. This in conjunction with
problems relating to lack of deployment versioning makes it quite hard for
consumers to handle these scenarios, often resulting in hours / day of backfill
handling. To make matters worse, almost always this results in some kind of
temporary feed & processes created in the system, ending up fairly messing up
the entities in the system. This jira essentially attempts to address this
issue cleanly. We attempted to get this solved few years back (FALCON-374 &
FALCON-297), but had to roll it back as the implementation had an issue
(copying of all lib jars). IMHO, neither then nor now, it seems to be against
any core principle/assumption on which Falcon was build. It certainly is
complex with numerous edge cases to consider (given the nature of the feature),
but that shouldn't be the reason for us to avoid this. Having said this, it is
quite possible that I might be missing something, if you call out specific
assumptions that this feature may possible be in violation then we can weigh in.
> Effective time in Entity updates.
> ---------------------------------
>
> Key: FALCON-1406
> URL: https://issues.apache.org/jira/browse/FALCON-1406
> Project: Falcon
> Issue Type: New Feature
> Reporter: sandeep samudrala
> Assignee: sandeep samudrala
> Attachments: FALCON-1406-initial.patch,
> effective_time_in_entity_updates.pdf
>
>
> Effective time with entity updates needs to be provided even with past time
> too. There was effective time capability provided in the past which gives the
> functionality to set an effective time for an entity with only current or
> future time(now + delay), which could not solve all the issues.
> Following are few scenarios which would require effective time to be
> available with time back in past.
> a) New code being deployed for an incompatible input data set which would
> leave instances with old code and new data.
> b) Bad code being pushed for which, the entity should be able to go back in
> time to replay(rerun) with new code.
> c) Orchestration level changes(good/bad) would need functionality to go back
> in time to start with.
> For reference: Linking all the Jiras that have been worked upon around
> effective time .
> https://issues.apache.org/jira/browse/FALCON-374
> https://issues.apache.org/jira/browse/FALCON-297
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