Startup stages of database "Nomount" , "Mount" , "Open"
There are three stages of startup of Oracle database which are as follows below: - Stage 1) No mount stage: - In this stage, Oracle reads pfile(parameter file) or spfile(server parameter file) to make the instance up and running. Instance: - SGA(System Global Area)+Background Process Note:- In this stage, the only instance will up and running not database. Location of pfile and spfile: - ORACLE_HOME/dbs Example: - Stage 2) Mount stage: - In mount stage, Oracle reads the "Control File" to make the database in mount stage. Example: - Stage 3) Open stage: - The final stage is the open stage. In this stage user can connects to the database to perform their activity. Example: -