What could be causing the fluctuation in ReplicaLag every 5 minutes in Oracle RDS?

Hello @RouseV,

When the size of the primary online redo log exceeds that of the standby redo log on the replica, it can lead to this issue.

If a standby redo log is utilized, real-time apply can be enabled in the Data Guard configuration, allowing Data Guard to recover redo data from the current standby redo log as it is being written by the RFS process. However, if the primary online redo log size surpasses that of the standby redo log on the replica, the standby redo log cannot be used. Consequently, when an archive log is generated on the primary, it is sent to the standby, and at that moment, the standby is recovered using that archive redo log.

In RDS Oracle, where the archive_lag_target is set to 5 minutes, the ReplicaLag fluctuates up and down every 5 minutes.