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<h1>Hardware Resources</h1>
<p>Effective querying requires enough operating memory and
quick hard drive access. Hard drive access time is important as the object will
be read from the physical location into the operating memory. However, hard
drive speed is not so critical for querying as it is for <a href="../insert_performance.htm">inserting</a>.</p>
<p>The following test uses a RAM drive to compare test results
with the hard drive:</p>
<p MadCap:conditions="Global.Primary:java" />
<p MadCap:conditions="Primary..NET">
<pre class="prettyprint" xml:space="preserve">QueryPerformanceBenchmark.cs: RunRamDiskTest
private void RunRamDiskTest()
{
InitForHardDriveTest();
Clean();
System.Console.WriteLine("Storing " + _count +
" objects of depth " + _depth
+ " on a hard drive:");
Open(ConfigureRamDrive());
Store();
Close();
Open(ConfigureRamDrive());
StartTimer();
IQuery query = objectContainer.Query();
query.Constrain(typeof(Item));
query.Descend("_name").Constrain("level1/1");
Item item = (Item)query.Execute().Next();
StopTimer("Select 1 object: " + item._name);
Close();
InitForRamDriveTest();
Clean();
System.Console.WriteLine("Storing " + _count +
" objects of depth " + _depth
+ " on a RAM disk:");
Open(ConfigureRamDrive());
Store();
Close();
Open(ConfigureRamDrive());
StartTimer();
query = objectContainer.Query();
query.Constrain(typeof(Item));
query.Descend("_name").Constrain("level1/1");
item = (Item)query.Execute().Next();
StopTimer("Select 1 object: " + 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>Test results:</p>
<p><i>Storing 30000 objects
of depth 3 on a hard drive:</i>
</p>
<p><i>Store 90000 objects:
6019ms</i>
</p>
<p><i>Select 1 object:
level1/1: 1515ms</i>
</p>
<p><i>Storing 30000 objects
of depth 3 on a RAM disk:</i>
</p>
<p><i>Store 90000 objects:
5264ms</i>
</p>
<p><i>Select 1 object:
level1/1: 1518ms</i>
</p>
<p>You can see that the difference in query performance is negligible.</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>
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