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https://issues.apache.org/jira/browse/KAFKA-4113?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16160493#comment-16160493
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Jay Kreps commented on KAFKA-4113:
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But I suppose you must be okay with that not happening too, since in steady
state you'll be joining data in the table with data in the stream at about the
same timestamp. I think my argument is that if you are okay with this behavior
in normal operation you should also be okay with it during bootstrapping (and
in many cases joining on future data and producing results that wouldn't occur
in steady state operation is not desirable).
> Allow KTable bootstrap
> ----------------------
>
> Key: KAFKA-4113
> URL: https://issues.apache.org/jira/browse/KAFKA-4113
> Project: Kafka
> Issue Type: New Feature
> Components: streams
> Reporter: Matthias J. Sax
> Assignee: Guozhang Wang
>
> On the mailing list, there are multiple request about the possibility to
> "fully populate" a KTable before actual stream processing start.
> Even if it is somewhat difficult to define, when the initial populating phase
> should end, there are multiple possibilities:
> The main idea is, that there is a rarely updated topic that contains the
> data. Only after this topic got read completely and the KTable is ready, the
> application should start processing. This would indicate, that on startup,
> the current partition sizes must be fetched and stored, and after KTable got
> populated up to those offsets, stream processing can start.
> Other discussed ideas are:
> 1) an initial fixed time period for populating
> (it might be hard for a user to estimate the correct value)
> 2) an "idle" period, ie, if no update to a KTable for a certain time is
> done, we consider it as populated
> 3) a timestamp cut off point, ie, all records with an older timestamp
> belong to the initial populating phase
> The API change is not decided yet, and the API desing is part of this JIRA.
> One suggestion (for option (4)) was:
> {noformat}
> KTable table = builder.table("topic", 1000); // populate the table without
> reading any other topics until see one record with timestamp 1000.
> {noformat}
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