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<h1>Monitor Freespace</h1>
<p>You can monitor the freespace-manager to find out more about the runtime behavior of your application.</p>
<h2>Configure the Freespace Monitoring Support</h2>
<p>To monitor the freespace manager you need to add the monitoring support to the db4o configuration.
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<pre class="prettyprint" xml:space="preserve">configuration.Common.Add(new FreespaceMonitoringSupport());</pre>
<div class="codesnippet-meta">FreespaceMonitoring.cs: Monitor the free-space system
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<pre class="prettyprint lang-vb" MadCap:conditions="Primary.Online" xml:space="preserve">configuration.Common.Add(New FreespaceMonitoringSupport())</pre>
<div class="codesnippet-meta">FreespaceMonitoring.vb: Monitor the free-space system
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<h2>The Freespace Statistics</h2>
<p><strong MadCap:conditions="Primary..NET">average freespace slot size</strong>: Tells you how big the average slot is. When you store larger objects, they need larger slots to fit it. </p>
<p><strong MadCap:conditions="Primary..NET">reused freespace slots/sec</strong>: Tells you how many slots can be reused. When an object is deleted or modified, its old slot is released and can be reused. If you modify and delete a lot of objects, but the slots cannot be reused, then the database-file will fragment. </p>
<p>When this number is low but the free-space increases and increases then you have a fragmentation issue. <a href="../../advanced_topics/defragment.htm">Defragment</a> your database. Use the <a href="../../configuration/id_system.htm">btree-id-system.</a></p>
<p><strong MadCap:conditions="Primary..NET">number of freespace slots</strong>: Tells you how many slots are used by the database. As more and more objects are stored, the slot count will increase.</p>
<p><strong MadCap:conditions="Primary..NET">total freespace</strong>: Tells you how much freespace there is in the database-file.A hight free-space number with a low reused slots number indicates database fragmentation. <a href="../../advanced_topics/defragment.htm">Defragment</a> your database. Use the <a href="../../configuration/id_system.htm">btree-id-system.</a></p>
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