Table of Contents

DOM history

From DataMiner 10.1.3/10.2.0 onwards, The DOM manager tracks the history of all changes done to the FieldValues of a DomInstance.

When a DomInstance is created or updated, a new HistoryChange object will be stored containing the created, updated, or deleted values. When a DomInstance is deleted, all history data is automatically deleted.

Prior to DataMiner version 10.3.9/10.4.0, this is done synchronously during DomInstance calls. This can cause these calls to take longer than expected. In case of a DomInstance delete, this delay could add up when there have been a lot of updates for that instance. From DataMiner 10.3.9/10.4.0 onwards, all DOM managers will by default execute the history actions asynchronously in the background. This prevents this delay on the DomInstance calls and thus improves their performance. However, note that it may still take a while for delete actions to be completed in the background.

Note
  • When designing a DOM manager, consider disabling the DOM history if these records are not required. This reduces the load on the database and reduces the amount of storage required. See Disabling the history or changing the storage behavior.
  • If for some reason the history storage is not working correctly, the CRUD operations for DOM instances will still continue to work, but the history will no longer be tracked. If this happens, an error will be logged for every failed history save. A notice in the Alarm Console will only be generated every hour to prevent an excessive number of notices.
  • It can happen that history records are still returned for a deleted DOM instance for a short time after this instance is deleted. This time can vary depending on the history settings, the number of records, and the database performance.

Disabling the history or changing the storage behavior

From DataMiner 10.3.9/10.4.0 onwards, you can override the default asynchronous save and delete behavior of the DOM instance history by setting the DomInstanceHistoryStorageBehavior option in the ModuleSettings. With this option, you can force the history to be saved synchronously, or you can disable history saving completely. For more information, see DomInstanceHistorySettings.

Changes to the field values

DomFieldValueChange

A change to a field value is stored in a DomFieldValueChange object, which has the following properties:

Property Type Description
FieldDescriptorId FieldDescriptorID The ID of the FieldDescriptor.
CrudType CrudType Determines whether this change is a create, update, or delete action.
ValueBefore IValueWrapper Value before the change (will be null when CrudType is set to "Create").
ValueAfter IValueWrapper Value after the change (will be null when CrudType is set to "Delete").

DomSectionChange

The DomSectionChange object bundles DomFieldValueChange objects together for a Section. It has the following properties:

Property Type Description
SectionId SectionID The ID of the Section.
FieldValueChanges List<DomFieldValueChange> A list of the DomFieldValueChange objects.

Changes to the status

Each time the status is changed, a DomInstanceStatusChange is saved, which has the following properties:

Property Type Description
StatusIdBefore string The ID of the status before the change.
StatusIdAfter string The ID of the status after the change.

HistoryChange

All the DomSectionChange and DomInstanceStatusChange objects for a DOM instance are saved to the database in a HistoryChange object (see DOM data storage).

A HistoryChange also contains the extra information of where, when, and by whom a change was initiated.

Property Type Filterable Description
ID Guid Yes Unique ID for this specific HistoryChange.
SubjectId IDMAObjectRef Yes The ID of the DomInstance.
Time DateTime Yes The time when the change was initiated.
FullUsername string Yes The user who initiated this change.
DmaId int Yes The ID of the DMA on which the change was initiated.
Changes IReadOnlyList<IChangeDescription> No A list of changes (requires a cast to one of the change types).

You can retrieve HistoryChange objects using the DomHelper class. You can filter them using HistoryChangeExposers.

Note

It is only possible to read HistoryChange items. Creating, updating, or deleting is reserved for the internal API.

Example:

// Get all history for a specific DomInstance
var filter = HistoryChangeExposers.SubjectID.Equal(domInstance.ID.ToFileFriendlyString());
var allHistory = domHelper.DomInstanceHistory.Read(filter);

// Cast the changes
var singleHistory = allHistory.First();
var sectionChanges = singleHistory.Changes.OfType<DomSectionChange>();
var statusChanges = singleHistory.Changes.OfType<DomInstanceStatusChange>();
Propose changes