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overview</a></li><li><a href=https://beam.apache.org/releases/javadoc/2.55.1/ target=_blank>Java SDK API reference <img src=/images/external-link-icon.png width=14 height=14 alt="External link."></a></li><li><a href=/documentation/sdks/java-dependencies/>Java SDK dependencies</a></li><li><a href=/documentation/sdks/java-extensions/>Java SDK extensions</a></li><li><a href=/documentation/sdks/java-thirdparty/>Java 3rd party extensions</a></li><li><a href=/documentation/sdks/java/testing/nexmark/>Nexmark benchmark suite</a></li><li><a href=/documentation/sdks/java/testing/tpcds/>TPC-DS benchmark suite</a></li><li><a href=/documentation/sdks/java-multi-language-pipelines/>Java multi-language pipelines quickstart</a></li></ul></li><li><span class=section-nav-list-title>Python</span><ul class=section-nav-list><li><a href=/documentation/sdks/python/>Python SDK overview</a></li><li><a href=https://beam.apache.org/releases/pydoc/2.55.1/ target=_blank>Python SDK API reference <img 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class=section-nav-list-title>Yaml</span><ul class=section-nav-list><li><a href=/documentation/sdks/yaml/>Yaml overview</a></li><li><a href=/documentation/sdks/yaml-udf/>Yaml User Defined Functions</a></li><li><a href=/documentation/sdks/yaml-combine/>Yaml Aggregation</a></li><li><a href=/documentation/sdks/yaml-errors/>Error handling</a></li><li><a href=/documentation/sdks/yaml-inline-python/>Inlining Python</a></li><li><a href=https://beam.apache.org/releases/yamldoc/current/ target=_blank>YAML API reference <img src=/images/external-link-icon.png width=14 height=14 alt="External link."></a></ul></li><li><span class=section-nav-list-title>SQL</span><ul class=section-nav-list><li><a href=/documentation/dsls/sql/overview/>Overview</a></li><li><a href=/documentation/dsls/sql/walkthrough/>Walkthrough</a></li><li><a href=/documentation/dsls/sql/shell/>Shell</a></li><li class=section-nav-item--collapsible><span class=section-nav-list-title>Apache Calcite dialect</span><ul class=section-nav-list><li><a href=/documentation/dsls/sql/calcite/overview/>Calcite support overview</a></li><li><a href=/documentation/dsls/sql/calcite/query-syntax/>Query syntax</a></li><li><a href=/documentation/dsls/sql/calcite/lexical/>Lexical structure</a></li><li><a href=/documentation/dsls/sql/calcite/data-types/>Data types</a></li><li><a href=/documentation/dsls/sql/calcite/scalar-functions/>Scalar functions</a></li><li><a href=/documentation/dsls/sql/calcite/aggregate-functions/>Aggregate functions</a></li></ul></li><li class=section-nav-item--collapsible><span class=section-nav-list-title>ZetaSQL dialect</span><ul class=section-nav-list><li><a href=/documentation/dsls/sql/zetasql/overview/>ZetaSQL support overview</a></li><li><a href=/documentation/dsls/sql/zetasql/syntax/>Function call rules</a></li><li><a href=/documentation/dsls/sql/zetasql/conversion-rules/>Conversion rules</a></li><li><a href=/documentation/dsls/sql/zetasql/query-syntax/>Query syntax</a></li><li><a href=/documentation/dsls/sql/zetasql/lexical/>Lexical structure</a></li><li><a href=/documentation/dsls/sql/zetasql/data-types/>Data types</a></li><li><a href=/documentation/dsls/sql/zetasql/operators/>Operators</a></li><li class=section-nav-item--collapsible><span class=section-nav-list-title>Scalar functions</span><ul class=section-nav-list><li><a href=/documentation/dsls/sql/zetasql/string-functions/>String functions</a></li><li><a href=/documentation/dsls/sql/zetasql/math-functions/>Mathematical functions</a></li><li><a href=/documentation/dsls/sql/zetasql/conditional-expressions/>Conditional expressions</a></li></ul></li><li><a href=/documentation/dsls/sql/zetasql/aggregate-functions/>Aggregate functions</a></li></ul></li><li class=section-nav-item--collapsible><span class=section-nav-list-title>Beam SQL extensions</span><ul class=section-nav-list><li><a href=/documentation/dsls/sql/extensions/create-external-table/>CREATE EXTERNAL TABLE</a></li><li><a href=/documentation/dsls/sql/extensions/windowing-and-triggering/>Windowing & triggering</a></li><li><a href=/documentation/dsls/sql/extensions/joins/>Joins</a></li><li><a href=/documentation/dsls/sql/extensions/user-defined-functions/>User-defined functions</a></li><li><a href=/documentation/dsls/sql/extensions/set/>SET pipeline options</a></li></ul></li></ul></li><li><span class=section-nav-list-title>DataFrames</span><ul class=section-nav-list><li><a href=/documentation/dsls/dataframes/overview/>Overview</a></li><li><a href=/documentation/dsls/dataframes/differences-from-pandas/>Differences from pandas</a></li><li><a href=https://github.com/apache/beam/tree/master/sdks/python/apache_beam/examples/dataframe target=_blank>Example pipelines <img src=/images/external-link-icon.png width=14 height=14 alt="External link."></a></li><li><a href=https://beam.apache.org/releases/pydoc/2.55.1/apache_beam.dataframe.html target=_blank>DataFrame API reference <img src=/images/external-link-icon.png width=14 height=14 alt="External link."></a></li></ul></li></ul></nav></div><nav class="page-nav clearfix" data-offset-top=90 data-offset-bottom=500><nav id=TableOfContents><ul><li><a href=#join-library>Join-library</a></li><li><a href=#sorter>Sorter</a><ul><li><a href=#caveats>Caveats</a></li><li><a href=#options>Options</a></li><li><a href=#example-usage-of-sortvalues>Example usage of <code>SortValues</code></a></li></ul></li></ul></nav></nav><div class="body__contained body__section-nav"><h1 id=apache-beam-java-sdk-extensions>Apache Beam Java SDK Extensions</h1><h2 id=join-library>Join-library</h2><p>Join-library provides inner join, outer left join, and outer right join functions. The aim |
| is to simplify the most common cases of join to a simple function call.</p><p>The functions are generic and support joins of any Beam-supported types. |
| Input to the join functions are <code>PCollections</code> of <code>Key</code> / <code>Value</code>s. Both |
| the left and right <code>PCollection</code>s need the same type for the key. All the join |
| functions return a <code>Key</code> / <code>Value</code> where <code>Key</code> is the join key and value is |
| a <code>Key</code> / <code>Value</code> where the key is the left value and right is the value.</p><p>For outer joins, the user must provide a value that represents <code>null</code> because <code>null</code> |
| cannot be serialized.</p><p>Example usage:</p><pre tabindex=0><code>PCollection<KV<String, String>> leftPcollection = ... |
| PCollection<KV<String, Long>> rightPcollection = ... |
| |
| PCollection<KV<String, KV<String, Long>>> joinedPcollection = |
| Join.innerJoin(leftPcollection, rightPcollection); |
| </code></pre><h2 id=sorter>Sorter</h2><p>This module provides the <code>SortValues</code> transform, which takes a <code>PCollection<KV<K, Iterable<KV<K2, V>>>></code> and produces a <code>PCollection<KV<K, Iterable<KV<K2, V>>>></code> where, for each primary key <code>K</code> the paired <code>Iterable<KV<K2, V>></code> has been sorted by the byte encoding of secondary key (<code>K2</code>). It is an efficient and scalable sorter for iterables, even if they are large (do not fit in memory).</p><h3 id=caveats>Caveats</h3><ul><li>This transform performs value-only sorting; the iterable accompanying each key is sorted, but <em>there is no relationship between different keys</em>, as Beam does not support any defined relationship between different elements in a <code>PCollection</code>.</li></ul><ul><li>Each <code>Iterable<KV<K2, V>></code> is sorted on a single worker using local memory and disk. This means that <code>SortValues</code> may be a performance and/or scalability bottleneck when used in different pipelines. For example, users are discouraged from using <code>SortValues</code> on a <code>PCollection</code> of a single element to globally sort a large <code>PCollection</code>. A (rough) estimate of the number of bytes of disk space utilized if sorting spills to disk is <code>numRecords * (numSecondaryKeyBytesPerRecord + numValueBytesPerRecord + 16) * 3</code>.</li></ul><h3 id=options>Options</h3><ul><li>The user can customize the temporary location used if sorting requires spilling to disk and the maximum amount of memory to use by creating a custom instance of <code>BufferedExternalSorter.Options</code> to pass into <code>SortValues.create</code>.</li></ul><h3 id=example-usage-of-sortvalues>Example usage of <code>SortValues</code></h3><pre tabindex=0><code>PCollection<KV<String, KV<String, Integer>>> input = ... |
| |
| // Group by primary key, bringing <SecondaryKey, Value> pairs for the same key together. |
| PCollection<KV<String, Iterable<KV<String, Integer>>>> grouped = |
| input.apply(GroupByKey.<String, KV<String, Integer>>create()); |
| |
| // For every primary key, sort the iterable of <SecondaryKey, Value> pairs by secondary key. |
| PCollection<KV<String, Iterable<KV<String, Integer>>>> groupedAndSorted = |
| grouped.apply( |
| SortValues.<String, String, Integer>create(BufferedExternalSorter.options())); |
| </code></pre></div></div><footer class=footer><div class=footer__contained><div class=footer__cols><div class="footer__cols__col footer__cols__col__logos"><div class=footer__cols__col__logo><img src=/images/beam_logo_circle.svg class=footer__logo alt="Beam logo"></div><div class=footer__cols__col__logo><img src=/images/apache_logo_circle.svg class=footer__logo alt="Apache logo"></div></div><div class=footer-wrapper><div class=wrapper-grid><div class=footer__cols__col><div class=footer__cols__col__title>Start</div><div class=footer__cols__col__link><a href=/get-started/beam-overview/>Overview</a></div><div class=footer__cols__col__link><a href=/get-started/quickstart-java/>Quickstart (Java)</a></div><div class=footer__cols__col__link><a href=/get-started/quickstart-py/>Quickstart (Python)</a></div><div class=footer__cols__col__link><a href=/get-started/quickstart-go/>Quickstart (Go)</a></div><div class=footer__cols__col__link><a href=/get-started/downloads/>Downloads</a></div></div><div class=footer__cols__col><div class=footer__cols__col__title>Docs</div><div class=footer__cols__col__link><a href=/documentation/programming-guide/>Concepts</a></div><div class=footer__cols__col__link><a href=/documentation/pipelines/design-your-pipeline/>Pipelines</a></div><div class=footer__cols__col__link><a href=/documentation/runners/capability-matrix/>Runners</a></div></div><div class=footer__cols__col><div class=footer__cols__col__title>Community</div><div class=footer__cols__col__link><a href=/contribute/>Contribute</a></div><div class=footer__cols__col__link><a href=https://projects.apache.org/committee.html?beam target=_blank>Team<img src=/images/external-link-icon.png width=14 height=14 alt="External link."></a></div><div class=footer__cols__col__link><a href=/community/presentation-materials/>Media</a></div><div class=footer__cols__col__link><a href=/community/in-person/>Events/Meetups</a></div><div class=footer__cols__col__link><a href=/community/contact-us/>Contact Us</a></div></div><div class=footer__cols__col><div class=footer__cols__col__title>Resources</div><div class=footer__cols__col__link><a href=/blog/>Blog</a></div><div class=footer__cols__col__link><a href=https://github.com/apache/beam>GitHub</a></div></div></div><div class=footer__bottom>© |
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