The default merge pipeline contains a set of predefined processors that implement the following rules for merging contact
Apply personal information from the source contact, for example, Nickname, First name and Last name, aliases, and details, to the merged contact. This action replaces each attribute, unless the corresponding attribute already contains a value.
Personal information attributes are merged together so that the updated contact record retains all existing entries, and adds any new entries from the contact record that will be made obsolete.
Engagement automation states
Apply this rule by replacing the implementation of the
Automation states are copied from the source contact to the target contact, including all custom data extensions. If both contacts have active automation states in the same automation plan, the state record with earlier creation time is selected by default.
Reassigned interactions associated with both source and target contact interactions to the target contact.
Interactions are renumbered in chronological order using the interaction
Copy the contact facets from the source contact to the target contact only if the corresponding facet is empty.
If the destination facet contains data then the target contact remains unchanged.
Merges standard contact facets with the target contact facet.
When merging, existing information on the target contact facet is kept, and if there is any conflicting information on the source contact facet, it is lost.
Standard contact facets such as a contact's preferred language are merged.
Contact Behavior Profile
Copy the Contact Behavior Profile when the target contact does not have a behavior profile already associated with it.
If the contact has one or more behavior profiles stored on it, then no data copies from the source contact to the target contact.
If both source and the target contact have data in their Key Behavior Cache, then both caches combine and their data is added to the target contact.
Key Behavior Cache
The Key Behavior Cache contains entries for campaigns, channels, custom values, goals, outcomes, page events and venues.
The system copies these entries across to the target contact during merge and then filters the cache entries.
The filtering logic is the same as for the update key behavior cache process.