oracle 12c alert log error I am using Oracle 12c Standard Edition Release 12.2.0.1.0. Everything works perfect. But while I was checking the alert log file I saw the following message several times. 

Error Message

An internal routine has requested a dump of selected redo.
This usually happens following a specific internal error, when
analysis of the redo logs will help Oracle Support with the
diagnosis.
It is recommended that you retain all the redo logs generated (by
all the instances) during the past 12 hours, in case additional
redo dumps are required to help with the diagnosis.


Any idea about this? I don't understand what it says so can somebody please help me out?

In response to @MichaelKutz' comment I can confirm that no ORA-nnn errors occur before or after the entry in the alert log file.
An Internal Routine Has Requested A Dump Of Selected Redo - Message Appears In Alert Log (Doc ID 2295361.1)


  ...
  
  SOLUTION
  
  You can ignore the message related to redo log if there is no error
  along with this information. Please note that for now, there is no way
  to disable the message by setting any event,  because these
  informative messages are useful in some cases if something goes wrong.
  
  ...