| <!DOCTYPE html> |
| <html lang="en"> |
| <head> |
| |
| |
| <title>Apache Jena - SDB Configuration</title> |
| <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> |
| <meta name="viewport" content="width=device-width, initial-scale=1.0"> |
| |
| <link href="/css/bootstrap.min.css" rel="stylesheet" media="screen"> |
| <link href="/css/bootstrap-extension.css" rel="stylesheet" type="text/css"> |
| <link href="/css/jena.css" rel="stylesheet" type="text/css"> |
| <link rel="shortcut icon" href="/images/favicon.ico" /> |
| |
| <script src="https://code.jquery.com/jquery-2.2.4.min.js" |
| integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" |
| crossorigin="anonymous"></script> |
| <script src="/js/jena-navigation.js" type="text/javascript"></script> |
| <script src="/js/bootstrap.min.js" type="text/javascript"></script> |
| |
| <script src="/js/improve.js" type="text/javascript"></script> |
| |
| |
| </head> |
| |
| <body> |
| |
| <nav class="navbar navbar-default" role="navigation"> |
| <div class="container"> |
| <div class="navbar-header"> |
| <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-ex1-collapse"> |
| <span class="icon-bar"></span> |
| <span class="icon-bar"></span> |
| <span class="icon-bar"></span> |
| </button> |
| <a class="navbar-brand" href="/index.html"> |
| <img class="logo-menu" src="/images/jena-logo/jena-logo-notext-small.png" alt="jena logo">Apache Jena</a> |
| </div> |
| |
| <div class="collapse navbar-collapse navbar-ex1-collapse"> |
| <ul class="nav navbar-nav"> |
| <li id="homepage"><a href="/index.html"><span class="glyphicon glyphicon-home"></span> Home</a></li> |
| <li id="download"><a href="/download/index.cgi"><span class="glyphicon glyphicon-download-alt"></span> Download</a></li> |
| <li class="dropdown"> |
| <a href="#" class="dropdown-toggle" data-toggle="dropdown"><span class="glyphicon glyphicon-book"></span> Learn <b class="caret"></b></a> |
| <ul class="dropdown-menu"> |
| <li class="dropdown-header">Tutorials</li> |
| <li><a href="/tutorials/index.html">Overview</a></li> |
| <li><a href="/documentation/fuseki2/index.html">Fuseki Triplestore</a></li> |
| <li><a href="/documentation/notes/index.html">How-To's</a></li> |
| <li><a href="/documentation/query/manipulating_sparql_using_arq.html">Manipulating SPARQL using ARQ</a></li> |
| <li><a href="/tutorials/rdf_api.html">RDF core API tutorial</a></li> |
| <li><a href="/tutorials/sparql.html">SPARQL tutorial</a></li> |
| <li><a href="/tutorials/using_jena_with_eclipse.html">Using Jena with Eclipse</a></li> |
| <li class="divider"></li> |
| <li class="dropdown-header">References</li> |
| <li><a href="/documentation/index.html">Overview</a></li> |
| <li><a href="/documentation/query/index.html">ARQ (SPARQL)</a></li> |
| <li><a href="/documentation/assembler/index.html">Assembler</a></li> |
| <li><a href="/documentation/tools/index.html">Command-line tools</a></li> |
| <li><a href="/documentation/rdfs/">Data with RDFS Inferencing</a></li> |
| <li><a href="/documentation/geosparql/index.html">GeoSPARQL</a></li> |
| <li><a href="/documentation/inference/index.html">Inference API</a></li> |
| <li><a href="/documentation/javadoc.html">Javadoc</a></li> |
| <li><a href="/documentation/ontology/">Ontology API</a></li> |
| <li><a href="/documentation/permissions/index.html">Permissions</a></li> |
| <li><a href="/documentation/extras/querybuilder/index.html">Query Builder</a></li> |
| <li><a href="/documentation/rdf/index.html">RDF API</a></li> |
| <li><a href="/documentation/rdfconnection/">RDF Connection - SPARQL API</a></li> |
| <li><a href="/documentation/io/">RDF I/O</a></li> |
| <li><a href="/documentation/rdfstar/index.html">RDF-star</a></li> |
| <li><a href="/documentation/shacl/index.html">SHACL</a></li> |
| <li><a href="/documentation/shex/index.html">ShEx</a></li> |
| <li><a href="/documentation/jdbc/index.html">SPARQL over JDBC</a></li> |
| <li><a href="/documentation/tdb/index.html">TDB</a></li> |
| <li><a href="/documentation/tdb2/index.html">TDB2</a></li> |
| <li><a href="/documentation/query/text-query.html">Text Search</a></li> |
| </ul> |
| </li> |
| |
| <li class="drop down"> |
| <a href="#" class="dropdown-toggle" data-toggle="dropdown"><span class="glyphicon glyphicon-book"></span> Javadoc <b class="caret"></b></a> |
| <ul class="dropdown-menu"> |
| <li><a href="/documentation/javadoc.html">All Javadoc</a></li> |
| <li><a href="/documentation/javadoc/arq/">ARQ</a></li> |
| <li><a href="/documentation/javadoc_elephas.html">Elephas</a></li> |
| <li><a href="/documentation/javadoc/fuseki2/">Fuseki</a></li> |
| <li><a href="/documentation/javadoc/geosparql/">GeoSPARQL</a></li> |
| <li><a href="/documentation/javadoc/jdbc/">JDBC</a></li> |
| <li><a href="/documentation/javadoc/jena/">Jena Core</a></li> |
| <li><a href="/documentation/javadoc/permissions/">Permissions</a></li> |
| <li><a href="/documentation/javadoc/extras/querybuilder/">Query Builder</a></li> |
| <li><a href="/documentation/javadoc/shacl/">SHACL</a></li> |
| <li><a href="/documentation/javadoc/tdb/">TDB</a></li> |
| <li><a href="/documentation/javadoc/text/">Text Search</a></li> |
| </ul> |
| </li> |
| |
| <li id="ask"><a href="/help_and_support/index.html"><span class="glyphicon glyphicon-question-sign"></span> Ask</a></li> |
| |
| <li class="dropdown"> |
| <a href="#" class="dropdown-toggle" data-toggle="dropdown"><span class="glyphicon glyphicon-bullhorn"></span> Get involved <b class="caret"></b></a> |
| <ul class="dropdown-menu"> |
| <li><a href="/getting_involved/index.html">Contribute</a></li> |
| <li><a href="/help_and_support/bugs_and_suggestions.html">Report a bug</a></li> |
| <li class="divider"></li> |
| <li class="dropdown-header">Project</li> |
| <li><a href="/about_jena/about.html">About Jena</a></li> |
| <li><a href="/about_jena/architecture.html">Architecture</a></li> |
| <li><a href="/about_jena/citing.html">Citing</a></li> |
| <li><a href="/about_jena/team.html">Project team</a></li> |
| <li><a href="/about_jena/contributions.html">Related projects</a></li> |
| <li><a href="/about_jena/roadmap.html">Roadmap</a></li> |
| <li class="divider"></li> |
| <li class="dropdown-header">ASF</li> |
| <li><a href="http://www.apache.org/">Apache Software Foundation</a></li> |
| <li><a href="http://www.apache.org/foundation/sponsorship.html">Become a Sponsor</a></li> |
| <li><a href="http://www.apache.org/licenses/LICENSE-2.0">License</a></li> |
| <li><a href="http://www.apache.org/security/">Security</a></li> |
| <li><a href="http://www.apache.org/foundation/thanks.html">Thanks</a></li> |
| </ul> |
| </li> |
| |
| |
| |
| |
| <li id="edit"><a href="https://github.com/apache/jena-site/edit/main/source/documentation/archive/sdb/configuration.md" title="Edit this page on GitHub"><span class="glyphicon glyphicon-pencil"></span> Edit this page</a></li> |
| </ul> |
| </div> |
| </div> |
| </nav> |
| |
| |
| <div class="container"> |
| <div class="row"> |
| <div class="col-md-12"> |
| <div id="breadcrumbs"> |
| |
|
|
|
|
|
|
|
|
|
|
|
|
| <ol class="breadcrumb">
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| <li><a href='/documentation'>DOCUMENTATION</a></li>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| <li><a href='/documentation/archive'>ARCHIVE</a></li>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| <li><a href='/documentation/archive/sdb'>SDB</a></li>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| <li class="active">CONFIGURATION</li>
|
|
|
|
|
|
|
|
|
| </ol>
|
|
|
|
|
|
|
| |
| |
| </div> |
| <h1 class="title">SDB Configuration</h1> |
| |
| <p>This page describes the configuration options available. These are |
| options for query processing, not for the database layout and |
| storage, which is controlled by |
| <a href="store_description.html" title="SDB/Store Description">store descriptions</a>.</p> |
| <h2 id="contents">Contents</h2> |
| <ul> |
| <li><a href="#setting-options">Setting Options</a></li> |
| <li><a href="#current-options">Current Options</a> |
| <ul> |
| <li><a href="#queries-over-all-named-graphs">Queries over all Named Graphs</a></li> |
| <li><a href="#streaming-over-jdbc">Streaming over JDBC</a></li> |
| <li><a href="#annotated-sql">Annotated SQL</a></li> |
| </ul> |
| </li> |
| </ul> |
| <h2 id="setting-options">Setting Options</h2> |
| <p>Options can be set globally, throughout the JVM, or on a per query |
| execution basis. SDB uses the same mechanism as |
| <a href="http://jena.sf.net/ARQ" title="http://jena.sf.net/ARQ">ARQ</a>.</p> |
| <p>There is a global context, which is give to each query |
| execution as it is created. Modifications to the global context |
| after the query execution is created are not seen by the query |
| execution. Modifications to the context of a single query execution |
| do not affect any other query execution nor the global context.</p> |
| <p>A context is a set of symbol/value pairs. Symbols are used created |
| internal to ARQ and SDB and access via Java constants. Values are |
| any Java object, together with the values <code>true</code> and <code>false</code>, which |
| are short for the constants of class <code>java.lang.Boolean</code>.</p> |
| <p>Setting globally:</p> |
| <pre><code> SDB.getContext().set(symbol, value) ; |
| </code></pre> |
| <p>Per query execution:</p> |
| <pre><code> QueryExecution qExec = QueryExecutionFactory.create(...) ; |
| qExec.getContext.set(symbol, value) ; |
| </code></pre> |
| <p>Setting for a query execution happens before any query compilation |
| or setup happens. Creation of a query execution object does not |
| compile the query, which happens when the appropriate <code>.exec</code> |
| method is called.</p> |
| <h2 id="current-options">Current Options</h2> |
| <table> |
| <thead> |
| <tr> |
| <th>Symbol</th> |
| <th>Effect</th> |
| <th>Default</th> |
| </tr> |
| </thead> |
| <tbody> |
| <tr> |
| <td><code>SDB.unionDefaultGraph</code></td> |
| <td>Query patterns on the default graph match against the union of the named graphs.</td> |
| <td>false</td> |
| </tr> |
| <tr> |
| <td><code>SDB.jdbcStream</code></td> |
| <td>Attempt to stream JDBC results.</td> |
| <td>true</td> |
| </tr> |
| <tr> |
| <td><code>SDB.jdbcFetchSize</code></td> |
| <td>Set the JDBC fetch size on the SQL query statements. Must be >= 0.</td> |
| <td>unset</td> |
| </tr> |
| <tr> |
| <td><code>SDB.streamGraphAPI</code></td> |
| <td>Stream Jena APIs (also requires <code>jdbcStream</code> and <code>jdbcFetchSize</code></td> |
| <td>false</td> |
| </tr> |
| <tr> |
| <td><code>SDB.annotateGeneratedSQL</code></td> |
| <td>Put SQL comments in SQL</td> |
| <td>true</td> |
| </tr> |
| </tbody> |
| </table> |
| <h3 id="queries-over-all-named-graphs">Queries over all Named Graphs</h3> |
| <p>All the named graphs can be treated as a single graph in two ways: |
| either set the SDB option above or use the URI that refers to RDF |
| merge of the named graphs (<code>urn:x-arq:UnionGraph</code>).</p> |
| <p>When querying the RDF merge of named graph, the default graph in |
| the store is not included.</p> |
| <p>This feature applies to queries only. It does not affect the |
| storage nor does it change loading.</p> |
| <p>To find out which named graph a triple can be found in, use <code>GRAPH</code> |
| as usual.</p> |
| <p>The following special IRIs exist for use as a graph name in <code>GRAPH</code> |
| only:</p> |
| <ul> |
| <li><code><urn:x-arq:DefaultGraph></code> – the default graph, even when |
| option for named union queries is set.</li> |
| <li><code><urn:x-arq:UnionGraph></code> – the union of all named graphs, even |
| when the option for named union queries is not set.</li> |
| </ul> |
| <h3 id="streaming-over-jdbc">Streaming over JDBC</h3> |
| <p>By default, SDB processes results from SQL statements in a |
| streaming fashion. It is important to close query execution |
| objects, especially if not consuming all the results, because that |
| causes the underlying JDBC result set to be closed. JDBC result |
| sets can be a scarce system resource.</p> |
| <p>If this option is set, but the JDBC connection is not streaming, |
| then this feature is harmless. Setting it false caused SDB to read |
| all results of an SQL statement at once, treating streamed |
| connections as unstreamed.</p> |
| <p>Note that this only streams results end-to-end if the underlying |
| JDBC connection itself is set up to stream. Most do not in the |
| default configuration to reduce transient resource peaks on the |
| server under load.</p> |
| <p>Setting the fetch size enables cursors in some databases but there |
| may be restrictions imposed by the database. See the documentation |
| for your database for details.</p> |
| <p>In addition, operations on the graph API can be made streaming by |
| also setting the Graph API to streaming.</p> |
| <h3 id="annotated-sql">Annotated SQL</h3> |
| <p>SQL generation can include SQL comments to show how SPARQL has been |
| turned into SQL. This option is <code>true</code> by default and always set |
| for the command <code>sdbprint</code>.</p> |
| <pre><code>SDB.getContext().setFalse(SDB.annotateGeneratedSQL) ; |
| </code></pre> |
| |
| |
| </div> |
| </div> |
| |
| </div> |
| |
| <footer class="footer"> |
| <div class="container" style="font-size:80%" > |
| <p> |
| Copyright © 2011–2022 The Apache Software Foundation, Licensed under the |
| <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>. |
| </p> |
| <p> |
| Apache Jena, Jena, the Apache Jena project logo, Apache and the Apache feather logos are trademarks of |
| The Apache Software Foundation. |
| <br/> |
| <a href="https://privacy.apache.org/policies/privacy-policy-public.html" |
| >Apache Software Foundation Privacy Policy</a>. |
| </p> |
| </div> |
| </footer> |
| |
| |
| <script type="text/javascript"> |
| var link = $('a[href="' + this.location.pathname + '"]'); |
| if (link != undefined) |
| link.parents('li,ul').addClass('active'); |
| </script> |
| |
| </body> |
| </html> |
