Explanation/Reference:
Explanation:
Consider using the following methods to optimize the time it takes to apply redo to physical standby databases.
* (B) Set Parallel Recovery to Twice the Number of CPUs on One Standby Host
* (E) During media recovery or Redo Apply, the redo log file is read, and data blocks that require redo application are parsed out. With parallel media recovery, these data blocks are subsequently distributed evenly to all recovery processes to be read into the buffer cache. The default is serial recovery or zero parallelism, which implies that the same recovery process reads the redo, reads the data blocks from disk, and applies the redo changes.
References: https://docs.oracle.com/cd/B19306_01/server.102/b14239/manage_ps.htm#BACHIBGG