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When Oracle creates the instance management files are created/identified as a part of the instance. The management files contain the structures of for an information. The management files even have the begin SCN and finish SCN numbers for all the info files utilized by Oracle for a given information. the essential structures for identification of the information lay within the management files for the information.
The info files shall have SCN numbers in headers and redo logs files contain all the SCN numbers for every dealing. The consistency is achieved by scrutiny the SCN between the management files and information files and so if necessary applying those transactions from the redo log files to fill the gaps by rolling forward those transactions and filling of the gap between the SCNs in control files and information files. this is often the technique for the recovery of databases.
They are very important and therefore these physical structures are multiplexed by Oracle and Oracle recommends that you simply would like the smallest amount three management files placed on 3 completely different disks for security.
If all the management files square measure lost and you are doing not have any backup management file otherwise you don’t have any produce management file command saved you have got countless issues to open the information. If you’re victimization RMAN, even those structures needed for distinguishing RMAN are stored within the management file. you’ll be able to manage the entries that square measure to be maintained within the management file by setting an format parameter.
The parameter CONTROL_FILE_RECORD_KEEP_TIME specifies the minimum variety of days before a reusable record within the management file is reused. within the event a replacement record must be further to a reusable section and also the oldest record has not aged enough, the record section expands. If this parameter is ready to, then reusable sections never expand, and records are reused as needed.