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Posted to commits@kafka.apache.org by bb...@apache.org on 2020/04/17 18:45:01 UTC
[kafka-site] branch asf-site updated: Equivalent to
cc4e3aa30207679f70f41abd2ca2c79a5d91ca9d on apache/kafka repo. (#262)
This is an automated email from the ASF dual-hosted git repository.
bbejeck pushed a commit to branch asf-site
in repository https://gitbox.apache.org/repos/asf/kafka-site.git
The following commit(s) were added to refs/heads/asf-site by this push:
new 0dffab2 Equivalent to cc4e3aa30207679f70f41abd2ca2c79a5d91ca9d on apache/kafka repo. (#262)
0dffab2 is described below
commit 0dffab2ee75e2420922c448224baf1902b1b8795
Author: Sönke Liebau <so...@opencore.com>
AuthorDate: Fri Apr 17 20:43:58 2020 +0200
Equivalent to cc4e3aa30207679f70f41abd2ca2c79a5d91ca9d on apache/kafka repo. (#262)
Equivalent to cc4e3aa30207679f70f41abd2ca2c79a5d91ca9d on apache/kafka repo.
Switch order of sections on tumbling and hopping windows in streams doc. Tumbling windows are defined as "special case of hopping time windows" - but hopping windows currently only explained later in the docs. (#8505)
Currently, tumbling windows are defined as "a special case of hopping time windows" in the streams docs, but hopping windows are only explained in a subsequent section.
I think it would make sense to switch the order of these paragraphs around. To me this also makes more sense semantically.
Testing
Built the site and checked that everything looks ok and html is valid (or at least didn't contain any new warnings that were caused by this change).
Reviewers: Bill Bejeck <bb...@apache.org>
---
25/streams/developer-guide/dsl-api.html | 76 ++++++++++++++++-----------------
1 file changed, 38 insertions(+), 38 deletions(-)
diff --git a/25/streams/developer-guide/dsl-api.html b/25/streams/developer-guide/dsl-api.html
index 5ad0791..d5a7917 100644
--- a/25/streams/developer-guide/dsl-api.html
+++ b/25/streams/developer-guide/dsl-api.html
@@ -55,8 +55,8 @@
</ul>
</li>
<li><a class="reference internal" href="#windowing" id="id19">Windowing</a><ul>
- <li><a class="reference internal" href="#tumbling-time-windows" id="id20">Tumbling time windows</a></li>
<li><a class="reference internal" href="#hopping-time-windows" id="id21">Hopping time windows</a></li>
+ <li><a class="reference internal" href="#tumbling-time-windows" id="id20">Tumbling time windows</a></li>
<li><a class="reference internal" href="#sliding-time-windows" id="id22">Sliding time windows</a></li>
<li><a class="reference internal" href="#session-windows" id="id23">Session Windows</a></li>
<li><a class="reference internal" href="#window-final-results" id="id31">Window Final Results</a></li>
@@ -3179,13 +3179,13 @@
</tr>
</thead>
<tbody valign="top">
- <tr class="row-even"><td><a class="reference internal" href="#windowing-tumbling"><span class="std std-ref">Tumbling time window</span></a></td>
+ <tr class="row-even"><td><a class="reference internal" href="#windowing-hopping"><span class="std std-ref">Hopping time window</span></a></td>
<td>Time-based</td>
- <td>Fixed-size, non-overlapping, gap-less windows</td>
+ <td>Fixed-size, overlapping windows</td>
</tr>
- <tr class="row-odd"><td><a class="reference internal" href="#windowing-hopping"><span class="std std-ref">Hopping time window</span></a></td>
+ <tr class="row-odd"><td><a class="reference internal" href="#windowing-tumbling"><span class="std std-ref">Tumbling time window</span></a></td>
<td>Time-based</td>
- <td>Fixed-size, overlapping windows</td>
+ <td>Fixed-size, non-overlapping, gap-less windows</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#windowing-sliding"><span class="std std-ref">Sliding time window</span></a></td>
<td>Time-based</td>
@@ -3197,39 +3197,6 @@
</tr>
</tbody>
</table>
- <div class="section" id="tumbling-time-windows">
- <span id="windowing-tumbling"></span><h5><a class="toc-backref" href="#id20">Tumbling time windows</a><a class="headerlink" href="#tumbling-time-windows" title="Permalink to this headline"></a></h5>
- <p>Tumbling time windows are a special case of hopping time windows and, like the latter, are windows based on time
- intervals. They model fixed-size, non-overlapping, gap-less windows.
- A tumbling window is defined by a single property: the window’s <em>size</em>.
- A tumbling window is a hopping window whose window size is equal to its advance interval.
- Since tumbling windows never overlap, a data record will belong to one and only one window.</p>
- <div class="figure align-center" id="id3">
- <img class="centered" src="/{{version}}/images/streams-time-windows-tumbling.png">
- <p class="caption"><span class="caption-text">This diagram shows windowing a stream of data records with tumbling windows. Windows do not overlap because, by
-definition, the advance interval is identical to the window size. In this diagram the time numbers represent minutes;
-e.g. t=5 means “at the five-minute mark”. In reality, the unit of time in Kafka Streams is milliseconds, which means
-the time numbers would need to be multiplied with 60 * 1,000 to convert from minutes to milliseconds (e.g. t=5 would
-become t=300,000).</span></p>
- </div>
- <p>Tumbling time windows are <em>aligned to the epoch</em>, with the lower interval bound being inclusive and the upper bound
- being exclusive. “Aligned to the epoch” means that the first window starts at timestamp zero. For example, tumbling
- windows with a size of 5000ms have predictable window boundaries <code class="docutils literal"><span class="pre">[0;5000),[5000;10000),...</span></code> — and <strong>not</strong>
- <code class="docutils literal"><span class="pre">[1000;6000),[6000;11000),...</span></code> or even something “random” like <code class="docutils literal"><span class="pre">[1452;6452),[6452;11452),...</span></code>.</p>
- <p>The following code defines a tumbling window with a size of 5 minutes:</p>
- <div class="highlight-java"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">java.time.Duration</span><span class="o">;</span>
-<span class="kn">import</span> <span class="nn">org.apache.kafka.streams.kstream.TimeWindows</span><span class="o">;</span>
-
-<span class="c1">// A tumbling time window with a size of 5 minutes (and, by definition, an implicit</span>
-<span class="c1">// advance interval of 5 minutes).</span>
-<span class="kt">Duration</span> <span class="n">windowSizeMs</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">5</span><span class="o">);</span>
-<span class="n">TimeWindows</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="n">windowSizeMs</span><span class="o">);</span>
-
-<span class="c1">// The above is equivalent to the following code:</span>
-<span class="n">TimeWindows</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="n">windowSizeMs</span><span class="o">).</span><span class="na">advanceBy</span><span class="o">(</span><span class="n">windowSizeMs</span><span class="o">);</span>
-</pre></div>
- </div>
- </div>
<div class="section" id="hopping-time-windows">
<span id="windowing-hopping"></span><h5><a class="toc-backref" href="#id21">Hopping time windows</a><a class="headerlink" href="#hopping-time-windows" title="Permalink to this headline"></a></h5>
<p>Hopping time windows are windows based on time intervals. They model fixed-sized, (possibly) overlapping windows.
@@ -3271,6 +3238,39 @@ milliseconds (e.g. t=5 would become t=300,000).</span></p>
corresponding window instance and the embedded key can be retrieved as <code class="docutils literal"><span class="pre">Windowed#window()</span></code> and <code class="docutils literal"><span class="pre">Windowed#key()</span></code>,
respectively.</p>
</div>
+ <div class="section" id="tumbling-time-windows">
+ <span id="windowing-tumbling"></span><h5><a class="toc-backref" href="#id20">Tumbling time windows</a><a class="headerlink" href="#tumbling-time-windows" title="Permalink to this headline"></a></h5>
+ <p>Tumbling time windows are a special case of hopping time windows and, like the latter, are windows based on time
+ intervals. They model fixed-size, non-overlapping, gap-less windows.
+ A tumbling window is defined by a single property: the window’s <em>size</em>.
+ A tumbling window is a hopping window whose window size is equal to its advance interval.
+ Since tumbling windows never overlap, a data record will belong to one and only one window.</p>
+ <div class="figure align-center" id="id3">
+ <img class="centered" src="/{{version}}/images/streams-time-windows-tumbling.png">
+ <p class="caption"><span class="caption-text">This diagram shows windowing a stream of data records with tumbling windows. Windows do not overlap because, by
+definition, the advance interval is identical to the window size. In this diagram the time numbers represent minutes;
+e.g. t=5 means “at the five-minute mark”. In reality, the unit of time in Kafka Streams is milliseconds, which means
+the time numbers would need to be multiplied with 60 * 1,000 to convert from minutes to milliseconds (e.g. t=5 would
+become t=300,000).</span></p>
+ </div>
+ <p>Tumbling time windows are <em>aligned to the epoch</em>, with the lower interval bound being inclusive and the upper bound
+ being exclusive. “Aligned to the epoch” means that the first window starts at timestamp zero. For example, tumbling
+ windows with a size of 5000ms have predictable window boundaries <code class="docutils literal"><span class="pre">[0;5000),[5000;10000),...</span></code> — and <strong>not</strong>
+ <code class="docutils literal"><span class="pre">[1000;6000),[6000;11000),...</span></code> or even something “random” like <code class="docutils literal"><span class="pre">[1452;6452),[6452;11452),...</span></code>.</p>
+ <p>The following code defines a tumbling window with a size of 5 minutes:</p>
+ <div class="highlight-java"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">java.time.Duration</span><span class="o">;</span>
+<span class="kn">import</span> <span class="nn">org.apache.kafka.streams.kstream.TimeWindows</span><span class="o">;</span>
+
+<span class="c1">// A tumbling time window with a size of 5 minutes (and, by definition, an implicit</span>
+<span class="c1">// advance interval of 5 minutes).</span>
+<span class="kt">Duration</span> <span class="n">windowSizeMs</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">5</span><span class="o">);</span>
+<span class="n">TimeWindows</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="n">windowSizeMs</span><span class="o">);</span>
+
+<span class="c1">// The above is equivalent to the following code:</span>
+<span class="n">TimeWindows</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="n">windowSizeMs</span><span class="o">).</span><span class="na">advanceBy</span><span class="o">(</span><span class="n">windowSizeMs</span><span class="o">);</span>
+</pre></div>
+ </div>
+ </div>
<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