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https://issues.apache.org/jira/browse/KAFKA-6560?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16395807#comment-16395807
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ASF GitHub Bot commented on KAFKA-6560:
---------------------------------------
guozhangwang closed pull request #4685: KAFKA-6560: Add docs for KIP-261
URL: https://github.com/apache/kafka/pull/4685
This is a PR merged from a forked repository.
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diff --git a/docs/streams/upgrade-guide.html b/docs/streams/upgrade-guide.html
index 1d5a342b2bb..f5c16c08cd2 100644
--- a/docs/streams/upgrade-guide.html
+++ b/docs/streams/upgrade-guide.html
@@ -34,9 +34,17 @@ <h1>Upgrade Guide and API Changes</h1>
</div>
<p>
- If you are using Java 7 and want to upgrade from 1.0.x to 1.1.0 you
don't need to make any code changes as the public API is fully backward
compatible.
- If you are using Java 8 method references in your Kafka Streams code
you might need to update your code to resolve method ambiguties.
- Hot-swaping the jar-file only might not work for this case.
+ If you want to upgrade from 1.1.x to 1.2.0 and you have customized
window store implementations on the <code>ReadOnlyWindowStore</code> interface
+ you'd need to update your code to incorporate the newly added public
APIs; otherwise you don't need to make any code changes.
+ See <a href="#streams_api_changes_120">below</a> for a complete list
of 1.2.0 API and semantic changes that allow you to advance your application
and/or simplify your code base.
+ </p>
+
+ <p>
+ If you want to upgrade from 1.0.x to 1.1.0 and you have customized
window store implementations on the <code>ReadOnlyWindowStore</code> interface
+ you'd need to update your code to incorporate the newly added public
APIs.
+ Otherwise, if you are using Java 7 you don't need to make any code
changes as the public API is fully backward compatible;
+ but if you are using Java 8 method references in your Kafka Streams
code you might need to update your code to resolve method ambiguities.
+ Hot-swaping the jar-file only might not work for this case.
See <a href="#streams_api_changes_110">below</a> for a complete list
of 1.1.0 API and semantic changes that allow you to advance your application
and/or simplify your code base.
</p>
@@ -64,12 +72,21 @@ <h1>Upgrade Guide and API Changes</h1>
See <a href="#streams_api_changes_0101">below</a> a complete list of
0.10.1 API changes that allow you to advance your application and/or simplify
your code base, including the usage of new features.
</p>
+ <!-- TODO: verify release verion and update `id` and `href` attributes
(also at other places that link to this headline) -->
+ <h3><a id="streams_api_changes_120"
href="#streams_api_changes_120">Streams API changes in 1.2.0</a></h3>
+ <p>
+ We have added support for methods in <code>ReadOnlyWindowStore</code>
which allows for querying a single window's key-value pair.
+ For users who have customized window store implementations on the
above interface, they'd need to update their code to implement the newly added
method as well.
+ For more details, see <a
href="https://cwiki.apache.org/confluence/display/KAFKA/KIP-261%3A+Add+Single+Value+Fetch+in+Window+Stores";>KIP-261</a>.
+ </p>
+
<h3><a id="streams_api_changes_110"
href="#streams_api_changes_110">Streams API changes in 1.1.0</a></h3>
<p>
- We have added support for methods in <code>ReadOnlyWindowStore</code>
which allows for querying <code>WindowStore</code>s without the neccesity of
providing keys.
+ We have added support for methods in <code>ReadOnlyWindowStore</code>
which allows for querying <code>WindowStore</code>s without the necessity of
providing keys.
+ For users who have customized window store implementations on the
above interface, they'd need to update their code to implement the newly added
method as well.
+ For more details, see <a
href="https://cwiki.apache.org/confluence/display/KAFKA/KIP-205%3A+Add+all%28%29+and+range%28%29+API+to+ReadOnlyWindowStore";>KIP-205</a>.
</p>
-
<p>
There is a new artifact <code>kafka-streams-test-utils</code> providing
a <code>TopologyTestDriver</code>, <code>ConsumerRecordFactory</code>, and
<code>OutputVerifier</code> class.
You can include the new artifact as a regular dependency to your unit
tests and use the test driver to test your business logic of your Kafka Streams
application.
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> Use single-point queries than range queries for windowed aggregation operators
> ------------------------------------------------------------------------------
>
> Key: KAFKA-6560
> URL: https://issues.apache.org/jira/browse/KAFKA-6560
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Guozhang Wang
> Assignee: Guozhang Wang
> Priority: Critical
> Labels: needs-kip
> Fix For: 1.2.0
>
>
> Today for windowed aggregations in Streams DSL, the underlying implementation
> is leveraging the fetch(key, from, to) API to get all the related windows for
> a single record to update. However, this is a very inefficient operation with
> significant amount of CPU time iterating over window stores. On the other
> hand, since the operator implementation itself have full knowledge of the
> window specs it can actually translate this operation into multiple
> single-point queries with the accurate window start timestamp, which would
> largely reduce the overhead.
> The proposed approach is to add a single fetch API to the WindowedStore and
> use that in the KStreamWindowedAggregate / KStreamWindowedReduce operators.
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