What do the messages “Cop: Initiating recovery activation” and “Capture: In point-in-time recovery” signify (4297133)

What do the messages “Cop: Initiating recovery activation” and “Capture: In point-in-time recovery” signify

Messages messages “Cop: Initiating recovery activation” and “Capture: In point-in-time recovery” are seen in event log.

Here is the event log portion covering the start of activation:

Notice   2017-10-17 17:16:57.975190 13186 1 Activation: Replicating according to target compatibility of "9.0.0"  (activating datasource o.SOURCESID) [module sys]

Notice   2017-10-17 17:16:57.976161 13186 1 Activation: Activation for recovery to SCN 2720178914 started   (activating datasource o.SOURCESID) [module ocf]

Here is the event log portion covering the start of Capture:

Notice   2017-10-17 17:17:16.313337 13232 1 Capture: Point-in-time recovery: recover from SCN 2720178914   (capturing from o.SOURCESID) [module oct]

The messages pertain to the use of Resume Replication feature in activation.

The messages log the fact that the activation is using the Resume Replication feature, where the activation starts processing the changes after a SCN # or a given log sequence #. This SCN or SEQNO (log sequence #) happens to be from a point in time in the past and not the current redolog. This is not the default behavior of activation process. 

The syntax for such activation is:

sp_ctrl>activate config SCN=<SCN number from which the activation should start>     (if activating after a particular SCN)

OR 

sp_ctrl>activate config SEQNO=<log sequence number from which the activation should start>     (if activating after a particular log sequence #)

The following excerpts about the feature are taken from SharePlex Release Notes for version 9 Resume Replication - resume replication after a catastrophic failure SharePlex introduces Resume Replication, a new method for the fast recovery of replication in a high availability environment, such as Oracle Data Guard. At the core of Resume Replication is the ability to reconcile to the SCN of the last transaction that was processed by SharePlex before the failover. To support Resume Replication, the following were added: * A new parameter named SP_OPO_UPDATE_SCN was added to track the SCNs. * A new show scn command was added in sp_ctrl to show the SCN of the last transaction applied by Post. * A new scn= option of the activate config command was added to enable activation to an SCN. *A new seqno= option of the activate config command was added to enable activation to a log sequence number. * A new show_scn utility is available for use in the recovery process, to ensure reconcile and re-activation to the correct SCN. This utility not only provides the correct SCNs, but also provides the correct command syntax and SCN number for each queue when multiple post queues are in use. IMPORTANT! To support the tracking of SCNs, make certain to run Database Setup during the SharePlex upgrade procedure to update the SharePlex tables. See the SharePlex Reference Guide for more information.