Steps Involve to Startup Database

Steps Involve to Startup Database 

Startup nomount:

->oracle will read the parameters file , the parameter file contains the SGA Parameters.
->SGA will allocate
->Will start the mandatory Backgrounf process.
->It will create the file called alert log file , contains the database activities

 diagnostic_dest  path the alert log file will create .

 ->Starting the instance


 Startup Mount:

 ->During mount state it reads the control file.
 ->Opens the controlfile to obtain the names and location of datafile and redolog files.
 ->In mount state can rename the datafiles.
 ->can enable or disable the archivelog
 ->can perform the recovery.


 Alter database open :

 ->It check and verify the control file and redolog file is present physical location or not .
 ->open the redolog and control files.



                                       
                                              |
                                              |OPEN
                                              |                                       
                                   ---------
                                 |
                                 | mount
                     - ---------
                   |
                   |Start nomount
     -----------
     Shutdown


Shutdown Process :

there are 4 types of shutdown process is there
   1.Shutdown Normal
   2.Shutdown Transactional
   3.Shutdown Immediate
   4.Shutdown Abort


  1.Shutdown Normal :

   ->No new connection are allowed.
   ->Server waits for all the connected users to disconnect before shutting down the DB.
   ->Buffer information (DBBC,redolog Buffer) will be written into the Disk.
   ->SGA memory allocation will be released.
   ->Terminated the Background Process.
   ->database is closed and dismounted

    Syntax: sys>>shutdown or shutdown normal
   ->It is default options


  2.Shutdown transactional:
  
   ->No new connection are allowed.
   ->Existing users cannot start the new transaction
   ->Connected users will be disconnect the session as soon as the current transaction is ends.
   ->shutdown proceeds all the transaction are completed
   ->Buffer information (DBBC,redolog Buffer) will be written into the Disk.
   ->SGA memory allocation will be released.
   ->Terminated the Background Process.
   ->database is closed and dismounted

    Syntax: shutdown transactional

  3.Shutdown Immediate :
 
   ->No new connection are allowed
   ->users will be terminate immediately & sql statements in process will be terminated
   ->Oracle will rollback the active transaction.
   ->Buffer information (DBBC,redolog Buffer) will be written into the Disk.
   ->SGA memory allocation will be released.
   ->Terminated the Background Process.
   ->database is closed and dismounted

     Syntax : sys>>shutdown immediate

  4.Shutdown abort :
   
    ->No new connection are allowed
    ->users will be terminate immediately & sql statements in process will be terminated
    ->uncommited transaction will be rollback
    ->Buffer information (DBBC,redolog Buffer) will be written into the Disk.
    ->instance will be terminated without closing the file
    ->database notclosed and dismounted.
    ->During the next startup system monitor system monitor(SMON) will perform instance crash recovery(ICR)

    Syntax : sys>> shutdown abort

    Note : we cannot take the consistance backup once we shutdown the DB with shutdown abort command