Home  >  Blog  >   Oracle DBA  > 

Oracle Database Startup and Shutdown Procedure

Rating: 5

There are various stages that the database undergoes before a database is opened for use. In this article, you will learn about the oracle database startup and shutdown procedure.


Want To Get DBA Training From Experts? Enroll Now For Free Demo On Oracle DBA Training.


Learn Oracle Database Startup and Shutdown Procedure

Startup Procedure

Nomount State:

This is the state when the control file, online redo log files, and the database files are closed and are not accessible. The Oracle instance is available. Some of the v$ views (dynamic performance views) are available during this state.

A database may be brought to this state to perform operations.

1. Creating a database.
2. Recreating control file.
Ex: V$session, v$instance, v$database etc.

 MindMajix YouTube Channel

Mount state:

This is the next phase through which the database passes. During this stage, the control file is opened and the existence of all the database files and online redo log files is verified.

A database may be brought to this state to perform operations like

  1.  Backup
  2.  Recovery of the system or undo datafile.
  3.  Change the database to archive log mode etc.
  4.  When you query v$database for the open_mode, we get the answer as mounted.    

[Related Article: Oracle DBA Tutorial]


The database is opened. During this stage, the datafiles and the online redo log files are opened and are ready to use. Oracle doesn’t allow you to open the database if any of the datafile or online redo log file is missing or is corrupted.

A database may be opened is read-only mode as well as in reading write mode. The status may be found by querying v$database dynamic performance view. The query for this is as below

Sql>select open_mode from v$database:

In the read-only mode, the database may be queried but one cannot perform the dml operations.

Note: To startup or shutdown the database, you need to logon as “sys as sysdba” or with any user account having sysdba role assigned.

There are other options available like one can start the database in a restricted mode. This is used during maintenance activities, upgrades etc. Only those users having restricted session privilege can logon into the database.

[Related Article: Oracle DBA Interview Questions]


Shutdown Procedure

Oracle has three shutdown modes namely normal, immediate and abort.

1. Shutdown normal:

This is the default mode of shutting down the database. During this state, oracle server waits for all the users to disconnect.

2. Shutdown Transactional:

Waits until all the transactions are completed and then shuts down the database. During this state, no new connections are permitted.

3. Shutdown immediate:

This option will disconnect all the sessions; roll back all the running transactions and shutdown the database. During the next startup, no instance recovery is needed.

4. Shutdown abort:

This option doesn’t roll back any transactions and simply brings down the database. In layman’s terms, it just likes pulling the power plug of the television. Any subsequent database startup needs an instance recovery to be initiated by smon.

Any backup taken after shutting down the database in abort mode will not be consistent. It is recommended to use the first three methods to shut down the database for a consistent backup.

[Related Article: How to Resize Bigfile Tablespace in Oracle]


Misconceptions about Shutdown abort:

From the information available, it might appear that using an abort option isn’t a good idea. But however, in the case of large databases, it may take a while and hence the option of abort can be judiciously utilized as below

1. Shu abort
2. startup restrict
3. Shu immediate
4. Startup mount restrict
This will be a clean shutdown and will be much quicker than the conventional methods. However, experienced dba always prefers to wait rather than use the previous options.


Explore Oracle DBA Sample Resumes! Download & Edit, Get Noticed by Top Employers! Download Now!


Related Articles:

How To Create TableSpaces - Oracle DBA

How to Set Undo Retention Time in Oracle

Join our newsletter

Stay updated with our newsletter, packed with Tutorials, Interview Questions, How-to's, Tips & Tricks, Latest Trends & Updates, and more ➤ Straight to your inbox!

Course Schedule
Oracle DBA TrainingMay 21 to Jun 05
Oracle DBA TrainingMay 23 to Jun 07
Oracle DBA TrainingMay 28 to Jun 12
Oracle DBA TrainingMay 30 to Jun 14
Last updated: 12 Apr 2022
About Author
Ravindra Savaram

Ravindra Savaram is a Content Lead at Mindmajix.com. His passion lies in writing articles on the most popular IT platforms including Machine learning, DevOps, Data Science, Artificial Intelligence, RPA, Deep Learning, and so on. You can stay up to date on all these technologies by following him on LinkedIn and Twitter.

Recommended Courses

1 /10