Missing change types

The missing change types are described in the following table:

Missing change type Description

DIRECT

For server-to-server connections, a contributing replica is found to have missing changes and the missing changes type is not INDIRECT.

This can include replicas that are deleted but not obsolete, as there isn't sufficient information to determine which server hosted the replica. Also, if the replica has been deleted, it's unlikely that a server will have more recent changes to fix the missing changes lockdown.

INDIRECT

For server-to-server connections, a contributing replica is found to have missing changes and the replica is:

  • In the list of replica IDs for the topology
  • Hosted by a server not involved in the connection
Note:

This excludes deleted replicas.

OBSOLETE

The contributing replica with missing changes is obsolete based on the existing definition of obsolete (deleted and all changes older than the purge delay).

This change type is only applicable when the global configuration property replication-purge-obsolete-replicas is set to true, which it is the default setting. This change type takes precedence over the other change types.

PREVIOUS

For local replicas connecting to the replication server, a replica's backend previously had missing changes. This is indicated by a null change number.

REPLICA

For local replicas connecting to the replication server, a replica is missing changes relative to its local replication server. This can happen when a backend is restored from an older backup.

Missing change actions

The missing change actions are described in the following table:

Missing change action Description

CONTINUE

Raise an alert but ignore the missing change and continue. The missing changes will be lost. For the PREVIOUS missing changes type, the persistent missing changes state (null change number) will be permanently cleared.

PAUSE

Raise an alert and pause update sending for the particular replica that is missing changes from the source server connected to, but otherwise continue replicating data. The pause will remain in effect until the connection for the replica is restarted.

SERVER

Use the value from the corresponding missing changes type configuration property on the replication server.