ForgottenKnowledge Class

  • Article

Represents knowledge that has been forgotten because of tombstone cleanup.

Namespace: Microsoft.Synchronization
Assembly: Microsoft.Synchronization (in microsoft.synchronization.dll)

Syntax

'Declaration
<SerializableAttribute> _
<XmlRootAttribute(Namespace:="https://schemas.microsoft.com/2008/03/sync/", ElementName:="forgottenKnowledge")> _
Public Class ForgottenKnowledge
    Inherits SyncKnowledge
    Implements ISerializable
'Usage
Dim instance As ForgottenKnowledge

[SerializableAttribute] 
[XmlRootAttribute(Namespace="https://schemas.microsoft.com/2008/03/sync/", ElementName="forgottenKnowledge")] 
public class ForgottenKnowledge : SyncKnowledge, ISerializable

[SerializableAttribute] 
[XmlRootAttribute(Namespace=L"https://schemas.microsoft.com/2008/03/sync/", ElementName=L"forgottenKnowledge")] 
public ref class ForgottenKnowledge : public SyncKnowledge, ISerializable

/** @attribute SerializableAttribute() */ 
/** @attribute XmlRootAttribute(Namespace="https://schemas.microsoft.com/2008/03/sync/", ElementName="forgottenKnowledge") */ 
public class ForgottenKnowledge extends SyncKnowledge implements ISerializable

SerializableAttribute 
XmlRootAttribute(Namespace="https://schemas.microsoft.com/2008/03/sync/", ElementName="forgottenKnowledge") 
public class ForgottenKnowledge extends SyncKnowledge implements ISerializable

Remarks

The forgotten knowledge tracks the maximum version of tombstones that have been cleaned up. When an item is deleted from the item store, the metadata for that item is kept, but the item is marked as deleted. Metadata for a deleted item is called a tombstone. Tombstones must be periodically cleaned up or they will eventually use too much space in the item store. When a tombstone is removed from the metadata, the forgotten knowledge must be updated to contain the version of the removed tombstone. Be aware that forgotten knowledge is an overestimation of which items have had their metadata removed. Therefore, the forgotten knowledge might also contain items that still have active entries in the metadata.

Sync Framework uses the forgotten knowledge to detect an out-of-date synchronization destination. For more information, see Managing Tombstones and Recovering an Out-of-Date Replica.

Inheritance Hierarchy

System.Object
   Microsoft.Synchronization.SyncKnowledge
    Microsoft.Synchronization.ForgottenKnowledge

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

See Also

Reference

ForgottenKnowledge Members
Microsoft.Synchronization Namespace