Custom metadata collisions

A custom metadata collision occurs when these events occur in the order shown:

1.One of these changes occurs:

oAn annotation is added with the same name to a given object on each of two systems in a replication topology, but the annotation has different content on the two systems.

The addition of an annotation to a given object on only one of the systems does not result in a custom metadata collision if the object does not have an annotation with the same name on the other system. In this case, the new annotation is replicated without conflict.

oDifferent changes are made to the content of a given annotation for a given object on each of the two systems in a replication topology.

oA change is made to the content of a given annotation for a given object on one system in a replication topology, and the same annotation is deleted on another system in the topology.

2.The change made on one of the systems is replicated to the other system.

If a collision occurs when a custom metadata change for a given object is replicated from one system (system A) in a replication topology to another system (system B) in the topology:

If the last change on system A is more recent than the last change on system B, HCP applies the change from system A to the custom metadata on system B

If the last change on system B is more recent than the last change on system A, HCP does not change the custom metadata on system B

Here are two examples of how HCP handles collisions when custom metadata changes for a given object are replicated from one system (system A) in a replication topology to another system (system B) in the topology.

Example 1

The object starts out with annotations named a1 and a2 on both system A and system B.

The table below shows a sequence of events in which the annotations for the object are changed and the changes are then replicated.

Sequence

Event

1

On system B, a client changes the content of a1.

2

On system A, a client makes a different change to the content of a1.

3

On system A, a client adds annotation a3 to the object.

4

On system B, a client adds annotation a3 with different content from the a3 added on system A.

5

The changes on system A are replicated to system B. The resulting annotations for the object on system B are:

a1 with the changed content from system A
a2 (unchanged)
a3 with the content added on system B

6

The changes on system B are replicated to system A. The resulting annotations for the object on system A are:

a1 with the changed content from system A
a2 (unchanged)
a3 with the content added on system B

Example 2

The object starts out with the annotations named a1, a2, and a3 on both system A and system B.

The table below shows a sequence of events in which the annotations for the object are changed and the changes are then replicated.

Sequence

Event

1

On system B, a client changes the content of a1.

2

On system A, a client deletes a1.

3

On system A, a client changes the content of a2.

4

On system B, a client changes the content of a2.

5

On system A, a client deletes a3.

6

On system B, a client changes the content of a3.

7

The changes on system A are replicated to system B. The resulting annotations for the object on system B are:

a2 with the changed content from system B
a3 with the changed content from system B

8

The changes on system B are replicated to system A, the resulting annotations for the object on system A are:

a2 with the changed content from system B
a3 with the changed content from system B

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