<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns:MadCap="http://www.madcapsoftware.com/Schemas/MadCap.xsd" MadCap:lastBlockDepth="2" MadCap:lastHeight="120" MadCap:lastWidth="624" MadCap:disableMasterStylesheet="true" MadCap:tocPath="Tuning|Main Operations Performance|Query Performance" MadCap:InPreviewMode="false" MadCap:RuntimeFileType="Topic" MadCap:TargetType="WebHelp" MadCap:PathToHelpSystem="../../../../" MadCap:HelpSystemFileName="index.xml" MadCap:SearchType="Stem"> <head><title>Indexing </title> <script type="text/javascript">/* <![CDATA[ */ window.onload = function(){ var pathToFlash = $('html').attr('MadCap:PathToHelpSystem') + 'Content/Resources/Code/ZeroClipboard.swf'; ZeroClipboard.setMoviePath(pathToFlash); function bindToClipBord(element,content){ var clip = new ZeroClipboard.Client(); clip.setText(content); clip.glue(element); }; if(location.protocol==='file:'){ $('.copylink-marker').remove(); } else{ $('.copylink-marker').each(function(){ var text = $(this).parent().parent().children('.prettyprint').html(); $(this).hover(function(){ bindToClipBord(this,text); }, function(){}); }); } prettyPrint(); }; /* ]]> */</script> <link href="../../../SkinSupport/MadCap.css" rel="stylesheet" /> <link href="../../../Resources/Stylesheets/OnlineStyle.css" rel="stylesheet" /> <script src="../../../Resources/Code/prettify.js"> </script> <script src="../../../Resources/Code/lang-vb.js"> </script> <script src="../../../Resources/Code/jquery.min.js"> </script> <script src="../../../Resources/Code/ZeroClipboard.js"> </script> <script src="../../../SkinSupport/MadCapAll.js" type="text/javascript"> </script> </head> <body> <p class="MCWebHelpFramesetLink" style="display: none;"><a href="../../../../index_CSH.html#tuning/main_operations_performance/query_performance/indexing.htm" style="">Open topic with navigation</a> </p> <div class="MCBreadcrumbsBox"><span class="MCBreadcrumbsPrefix">You are here: </span><a class="MCBreadcrumbsLink" href="../../../tuning.htm">Tuning</a><span class="MCBreadcrumbsDivider"> > </span><a class="MCBreadcrumbsLink" href="../../main_operations_performance.htm">Main Operations Performance</a><span class="MCBreadcrumbsDivider"> > </span><a class="MCBreadcrumbsLink" href="../query_performance.htm">Query Performance</a><span class="MCBreadcrumbsDivider"> > </span><span class="MCBreadcrumbs">Indexing</span> </div> <p> <script type="text/javascript">/*<![CDATA[*/document.write('<a href="' + location.href +'">'); document.write("Direct Link"); document.write('</a>');/*]]>*/</script> </p> <p> </p> <h1>Indexing</h1> <p>Using indexes is always a good idea to improve query performance. The following test illustrates index performance impact:</p> <p MadCap:conditions="Global.Primary:java" /> <p MadCap:conditions="Primary..NET"> <pre class="prettyprint" xml:space="preserve">QueryPerformanceBenchmark.cs: RunIndexTest private void RunIndexTest() { Init(); System.Console.WriteLine("Storing " + _count + " objects with " + _depth + " levels of embedded objects:"); Clean(); System.Console.WriteLine(" - no index"); Open(Configure()); Store(); Close(); Open(Configure()); StartTimer(); IQuery query = objectContainer.Query(); query.Constrain(typeof(Item)); query.Descend("_name").Constrain("level1/2"); IList result = query.Execute(); Item item = (Item)result[0]; StopTimer("Querying object with string field: " + item._name); Close(); System.Console.WriteLine(" - index on string field"); // Open to create index Open(ConfigureIndex()); Close(); Open(Configure()); StartTimer(); query = objectContainer.Query(); query.Constrain(typeof(Item)); query.Descend("_name").Constrain("level1/2"); result = query.Execute(); item = (Item)result[0]; StopTimer("Querying object with string field: " + item._name); Close(); }</pre> <pre class="prettyprint" xml:space="preserve">QueryPerformanceBenchmark.cs: InitForHardDriveTest private void InitForHardDriveTest() { _count = 10000; _depth = 3; _filePath = "performance.db4o"; _isClientServer = false; }</pre> <pre class="prettyprint" xml:space="preserve">QueryPerformanceBenchmark.cs: ConfigureRamDrive private IConfiguration ConfigureRamDrive() { IConfiguration config = Db4oFactory.NewConfiguration(); config.FlushFileBuffers(true); return config; }</pre> </p> <p MadCap:conditions="Global.Primary:net" /> <p>Results from the test machine:</p> <p><i>Storing 10000 objects with 3 levels of embedded objects:</i> </p> <p><i> - no index</i> </p> <p><i>Store 30000 objects: 2228ms</i> </p> <p><i>Querying object with String field: level1/2: 461ms</i> </p> <p><i> - index on String field</i> </p> <p><i>Querying object with String field: level1/2: 460ms</i> </p> <p MadCap:conditions="Primary.Online">Download example code:</p> <p MadCap:conditions="Primary.Online"> <MadCap:conditionalText MadCap:conditions="Primary..NET,Primary.c#,Primary.All languages"><a href="queryperformancecs.zip">c# </a> </MadCap:conditionalText> </p> <script type="text/javascript" src="../../../SkinSupport/MadCapBodyEnd.js"> </script> </body> </html>