Analysis of information sources in references of the Wikipedia article "Redo log" in English language version.
I've referred to two types of redo log file: online and archived.
Standby redo logs (SRL) on the disaster recovery site act as the counterpart to the primary database's online redo logs (ORL) and allow the remote site to receive redo more efficiently.
[...] when a log switch occurs, the contents of the current redo log are written out to an archived redo log by the ARCn process. These logs are also referred to as offline redo logs or simply archive logs.
Primary and physical standby databases are synchronized through a service called Redo Apply, which recovers the redo data from the primary database and applies the redo to the standby database. [...] Synchronization between the primary and [logical] standby databases is achieved through a service named SQL Apply, which transforms the redo data from the primary database into SQL statements and then executes the SQL statements on the standby database.
Instance recovery has two phases: roll forward and roll back.
An incarnation as per the Oracle documentation is a separate version of the database.
The current redo log is always online, unlike archived copies of a redo log. Therefore, the online redo log is usually referred to as simply the redo log.
A standby redo log is similar to an online redo log, except that a standby redo log is used to store redo data received from another database.
