Gap_Timeout=minutes

    Specifies the maximum number of minutes that the standby database
    (LRS process) should wait for a gap in the replication data
    sequence to be resolved.

    Applicable to:              Standby database
    Required or Optional:       Optional
    Default Value:              5 minutes
    Minimum Value:              1 minute
    Maximum Value:              4320 minutes (3 days)

    If a gap in the replication data sequence is not resolved in the
    period of time allowed, the LRS process:

    1. Assumes that the node sending the message has failed

    2. Terminates replication operations immediately

    You must restart replication operations manually to resolve the
    situation.