vcrfxia commented on code in PR #13622:
URL: https://github.com/apache/kafka/pull/13622#discussion_r1177130156
##########
docs/streams/core-concepts.html:
##########
@@ -328,13 +328,17 @@ <h3 class="anchor-heading"><a
id="streams_out_of_ordering" class="anchor-link"><
for stateful operations such as aggregations and joins, however,
out-of-order data could cause the processing logic to be incorrect. If users
want to handle such out-of-order data, generally they need to allow their
applications
to wait for longer time while bookkeeping their states during the wait
time, i.e. making trade-off decisions between latency, cost, and correctness.
In Kafka Streams specifically, users can configure their window
operators for windowed aggregations to achieve such trade-offs (details can be
found in <a
href="/{{version}}/documentation/streams/developer-guide"><b>Developer
Guide</b></a>).
- As for Joins, users have to be aware that some of the out-of-order
data cannot be handled by increasing on latency and cost in Streams yet:
+ As for Joins, users may use <a
href="/{{version}}/documentation/streams/developer-guide/dsl-api.html#versioned-state-stores">versioned
state stores</a> to address concerns with out-of-order data, but out-of-order
data will not be handled by default:
</p>
<ul>
- <li> For Stream-Stream joins, all three types (inner, outer, left)
handle out-of-order records correctly, but the resulted stream may contain
unnecessary leftRecord-null for left joins, and leftRecord-null or
null-rightRecord for outer joins. </li>
- <li> For Stream-Table joins, out-of-order records are not handled
(i.e., Streams applications don't check for out-of-order records and just
process all records in offset order), and hence it may produce unpredictable
results. </li>
- <li> For Table-Table joins, out-of-order records are not handled
(i.e., Streams applications don't check for out-of-order records and just
process all records in offset order). However, the join result is a changelog
stream and hence will be eventually consistent. </li>
+ <li> For Stream-Stream joins, all three types (inner, outer, left)
handle out-of-order records correctly, but the resulting stream may contain
unnecessary leftRecord-null for left joins, and leftRecord-null or
null-rightRecord for outer joins.
Review Comment:
Here's the PR targeted at 3.4: https://github.com/apache/kafka/pull/13642
Based on the ticket (https://issues.apache.org/jira/browse/KAFKA-10847), it
looks like you'll want to backport this all the way to 3.1.
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