We all know that the LGWR flushes redo log entry from redo log buffer to the online redo log file. So I want to know whether there can be any condition apart from any recovery process where the redo entry has to be transferred from redo log file to data file, and which process does it? I mean that my database is 100% up and running, so is there any chance where such a condition can come about where a redo entry has to be applied directly from redo log file to data file.
Unless you are using Data Guard, redo is never read from the online redo logs unless you are performing a recovery operation on your database. All of the changed blocks are still in the buffer cache and will be written to the datafiles by the DBWn process. This occurs when a checkpoint happens.
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