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<h1>Configuration</h1>
<P>db4o provides a wide range of configuration options to help you meet your performance and reliability requirements. The following example shows how different configurations affect update performance:</P>
<p MadCap:conditions="Global.Primary:java" />
<p MadCap:conditions="Primary..NET">
<pre class="prettyprint" xml:space="preserve">UpdatePerformanceBenchmark.cs: RunConfigurationTest
private void RunConfigurationTest()
{
System.Console.WriteLine(
"Update test with different configurations");
//
Clean();
Init();
System.Console.WriteLine("Update test: default configurations");
Open(Db4oFactory.NewConfiguration());
Store();
UpdateItems(90);
Close();
//
Clean();
System.Console.WriteLine("Update test: memory IO adapter");
Open(Configure());
Store();
UpdateItems(90);
Close();
//
Clean();
System.Console.WriteLine("Update test: cascade on Update");
Open(ConfigureCascade());
Store();
UpdateTopLevelItems(90);
Close();
//
Clean();
System.Console.WriteLine("Update test: Transparent Persistence");
Open(ConfigureTP());
StoreActivatableItems();
UpdateActivatableItems(90);
Close();
}</pre>
<pre class="prettyprint" xml:space="preserve">UpdatePerformanceBenchmark.cs: UpdateItems
private void UpdateItems(int count)
{
StartTimer();
IObjectSet result = objectContainer.QueryByExample(null);
for (int i = 0; i < count; i++)
{
if (result.HasNext())
{
Item item = (Item)result.Next();
item._name = "Updated";
Update(item);
}
else
{
count = i;
break;
}
}
StopTimer("Updated " + count + " items");
}</pre>
<pre class="prettyprint" xml:space="preserve">UpdatePerformanceBenchmark.cs: UpdateTopLevelItems
private void UpdateTopLevelItems(int count)
{
StartTimer();
IQuery query = objectContainer.Query();
query.Constrain(typeof(Item));
query.Descend("_name").Constrain("level0").StartsWith(true);
IObjectSet result = query.Execute();
for (int i = 0; i < count; i++)
{
if (result.HasNext())
{
Item item = (Item)result.Next();
item._name = "Updated";
Update(item);
}
else
{
count = i;
break;
}
}
StopTimer("Updated " + count + " items");
}</pre>
<pre class="prettyprint" xml:space="preserve">UpdatePerformanceBenchmark.cs: UpdateActivatableItems
private void UpdateActivatableItems(int count)
{
StartTimer();
IQuery Query = objectContainer.Query();
Query.Constrain(typeof(ActivatableItem));
Query.Descend("_name").Constrain("level0").StartsWith(true);
IObjectSet result = Query.Execute();
for (int i = 0; i < count; i++)
{
if (result.HasNext())
{
ActivatableItem item = (ActivatableItem)result.Next();
item.Name = "Updated";
Update(item);
}
else
{
count = i;
break;
}
}
StopTimer("Updated " + count + " items");
}</pre>
<pre class="prettyprint" xml:space="preserve">UpdatePerformanceBenchmark.cs: Configure
private IConfiguration Configure()
{
IConfiguration config = Db4oFactory.NewConfiguration();
// using MemoryIoAdapter improves the performance
// by replacing the costly disk IO operations with
// memory access
config.Io(new MemoryIoAdapter());
return config;
}</pre>
<pre class="prettyprint" xml:space="preserve">UpdatePerformanceBenchmark.cs: ConfigureCascade
private IConfiguration ConfigureCascade()
{
IConfiguration config = Db4oFactory.NewConfiguration();
// CascadeOnUpdate can be a performance-killer for
// deep object hierarchies
config.ObjectClass(typeof(Item)).CascadeOnUpdate(true);
return config;
}</pre>
<pre class="prettyprint" xml:space="preserve">UpdatePerformanceBenchmark.cs: ConfigureTP
private IConfiguration ConfigureTP()
{
IConfiguration config = Db4oFactory.NewConfiguration();
// With Transparent Persistence enabled only modified
// objects are written to disk. This allows to achieve
// better performance
config.ObjectClass(typeof(Item)).CascadeOnUpdate(true);
return config;
}</pre>
<pre class="prettyprint" xml:space="preserve">UpdatePerformanceBenchmark.cs: ActivatableItem
public class ActivatableItem : IActivatable
{
private string _name;
public ActivatableItem _child;
[System.NonSerialized]
IActivator _activator;
public void Bind(IActivator activator)
{
if (_activator == activator)
{
return;
}
if (activator != null && _activator != null)
{
throw new System.InvalidOperationException();
}
_activator = activator;
}
public void Activate(ActivationPurpose purpose)
{
if (_activator == null) return;
_activator.Activate(purpose);
}
public ActivatableItem()
{
}
public ActivatableItem(string name, ActivatableItem child)
{
Name = name;
_child = child;
}
public string Name
{
get
{
return _name;
}
set
{
_name = value;
}
}
}</pre>
</p>
<p MadCap:conditions="Global.Primary:net" />
<P>The results:</P>
<P>
<I>Update test with different configurations</I>
</P>
<P>
<I>Update test: default configurations</I>
</P>
<P>
<I>Store 90000 objects: 7869ms</I>
</P>
<P>
<I>Updated 90 items: 471ms</I>
</P>
<P>
<I>Update test: memory IO adapter</I>
</P>
<P>
<I>Store 90000 objects: 6622ms</I>
</P>
<P>
<I>Updated 90 items: 289ms</I>
</P>
<P>
<I>Update test: cascade on update</I>
</P>
<P>
<I>Store 90000 objects: 6848ms</I>
</P>
<P>
<I>Updated 90 items: 1531ms</I>
</P>
<P>
<I>Update test: Transparent Persistence</I>
</P>
<P>
<I>Store 90000 objects: 6604ms</I>
</P>
<P>
<I>Updated 90 items: 1297ms</I>
</P>
<P>From the results you can see that MemoryIoAdapter allows to improve performance, CascadeOnUpdate option results in a considerable drop of performance, and Transparent Persistence makes it better again.</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="updateperformancecs.zip">c# </a>
</MadCap:conditionalText>
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