Size of the database

There are at least two ways to determine the size of your Oracle database:

  1. Total size of datafiles that make up tablespaces of the database
  2. Total size of tables and indexes in the database

Method 1

This method sums the total size of datafiles in the DB. Details can be found in the views v$datafile and dba_data_files. This will give your the number of MB allocated to your database:

SELECT sum(bytes/1048576) 
FROM dba_data_files

Remember, a megabyte is not 1000000 bytes but 1024*1024 bytes.

Method 2

Sums the total of extents used for the database. It will not tell you if the extent is 10% or 90% full. Details are found in the dba_extent view.

SELECT sum(bytes/1048576)
FROM dba_extents;
This will give you the total number of MB used by your database.

Try both methods and see for yourself.

For More Information

  • What do you think about this tip? E-mail the editor at

    Requires Free Membership to View

This was first published in May 2002

There are Comments. Add yours.

TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.