ableegoldman commented on a change in pull request #9264:
URL: https://github.com/apache/kafka/pull/9264#discussion_r485314713
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File path: docs/streams/developer-guide/dsl-api.html
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@@ -3286,13 +3306,33 @@ <h5><a class="toc-backref" href="#id34">KTable-KTable
Foreign-Key
<div class="section" id="sliding-time-windows">
<span id="windowing-sliding"></span><h5><a
class="toc-backref" href="#id22">Sliding time windows</a><a class="headerlink"
href="#sliding-time-windows" title="Permalink to this headline"></a></h5>
<p>Sliding windows are actually quite different from
hopping and tumbling windows. In Kafka Streams, sliding windows
- are used only for <a class="reference internal"
href="#streams-developer-guide-dsl-joins"><span class="std std-ref">join
operations</span></a>, and can be specified through the
- <code class="docutils literal"><span
class="pre">JoinWindows</span></code> class.</p>
- <p>A sliding window models a fixed-size window that
slides continuously over the time axis; here, two data records are
+ are used for <a class="reference internal"
href="#streams-developer-guide-dsl-joins"><span class="std std-ref">join
operations</span></a>, specified by using the
+ <code class="docutils literal"><span
class="pre">JoinWindows</span></code> class, and windowed aggregations,
specified by using the code class="docutils literal"><span
class="pre">SlidingWindows</span></code> class.</p>
Review comment:
```suggestion
<code class="docutils literal"><span
class="pre">JoinWindows</span></code> class, and windowed aggregations,
specified by using the <code class="docutils literal"><span
class="pre">SlidingWindows</span></code> class.</p>
```
##########
File path: docs/streams/developer-guide/dsl-api.html
##########
@@ -3286,13 +3306,33 @@ <h5><a class="toc-backref" href="#id34">KTable-KTable
Foreign-Key
<div class="section" id="sliding-time-windows">
<span id="windowing-sliding"></span><h5><a
class="toc-backref" href="#id22">Sliding time windows</a><a class="headerlink"
href="#sliding-time-windows" title="Permalink to this headline"></a></h5>
<p>Sliding windows are actually quite different from
hopping and tumbling windows. In Kafka Streams, sliding windows
- are used only for <a class="reference internal"
href="#streams-developer-guide-dsl-joins"><span class="std std-ref">join
operations</span></a>, and can be specified through the
- <code class="docutils literal"><span
class="pre">JoinWindows</span></code> class.</p>
- <p>A sliding window models a fixed-size window that
slides continuously over the time axis; here, two data records are
+ are used for <a class="reference internal"
href="#streams-developer-guide-dsl-joins"><span class="std std-ref">join
operations</span></a>, specified by using the
+ <code class="docutils literal"><span
class="pre">JoinWindows</span></code> class, and windowed aggregations,
specified by using the code class="docutils literal"><span
class="pre">SlidingWindows</span></code> class.</p>
+ <p>A sliding window models a fixed-size window that
slides continuously over the time axis. In this model, two data records are
said to be included in the same window if (in the
case of symmetric windows) the difference of their timestamps is
- within the window size. Thus, sliding windows are
not aligned to the epoch, but to the data record timestamps. In
- contrast to hopping and tumbling windows, the
lower and upper window time interval bounds of sliding windows are
- <em>both inclusive</em>.</p>
+ within the window size. As a sliding window moves
along the time axis, records may fall into multiple snapshots of
+ the sliding window, but each unique combination of
records appears only in one sliding window snapshot.</p>
+ <p>The following code defines a sliding window with a
time difference of 10 minutes and a grace period of 30 minutes:</p>
+ <div class="highlight-java"><div
class="highlight"><pre><span></span><span class="kn">import</span> <span
class="nn">org.apache.kafka.streams.kstream.SlidingWindows</span><span
class="o">;</span>
+
+<span class="c1">// A sliding time window with a time difference of 10 minutes
and grace period of 30 minutes</span>
+<span class="kt">Duration</span> <span class="n">timeDifferenceMs</span> <span
class="o">=</span> <span class="n">Duration</span><span class="o">.</span><span
class="na">ofMinutes</span><span class="o">(</span><span
class="mi">10</span><span class="o">);</span>
+<span class="kt">Duration</span> <span class="n">gracePeriodMs</span> <span
class="o">=</span> <span class="n">Duration</span><span class="o">.</span><span
class="na">ofMinutes</span><span class="o">(</span><span
class="mi">30</span><span class="o">);</span>
+<span class="n">SlidingWindows</span><span class="o">.</span><span
class="na">withTimeDifferenceAndGrace</span><span class="o">(</span><span
class="n">timeDifferenceMs</span><span class="o">,</span><span
class="n">gracePeriodMs</span><span class="o">);</span>
+</pre></div>
+ <div class="admonition note">
+ <p><b>Note</b></p>
+ <p>Sliding windows <em>require</em> that you set
a grace period, as shown above. For time windows and session windows,
+ setting the grace period is optional and
defaults to 24 hours.</p>
+ </div>
+ <div class="figure align-center" id="id35">
+ <img class="centered"
src="/{{version}}/images/streams-sliding-windows.png">
+ <p class="caption"><span
class="caption-text">This diagram shows windowing a stream of data records with
sliding windows. The overlap of
+ the sliding window snapshots varies depending
on the record times. In this diagram, the time numbers represent miliseconds.
For example,
+ t=5 means “at the five milisecond
mark”.</span></p>
Review comment:
I rendered the site locally and there's something weird going on here.
Seems like you can't use literal `"`. Look at what the other captions do, seems
like it might be `“`
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