Are you tired of running out of storage space on your Oracle database? Do you want to optimize your database performance and avoid costly downtime?

Look no further!

In this article, we’ll discuss how to find unused objects in an Oracle database and how to remove them to free up valuable space.

First, let’s define what we mean by "unused objects." These are typically old or forgotten tables, views, procedures, and other database objects that are no longer being used by your application or users. Over time, these objects can accumulate and take up a significant amount of storage space in your database. By removing them, you can free up valuable resources and improve the overall performance of your database.

Now, let’s dive into the steps for finding unused objects in an Oracle database:

Step 1: Use the DBA_OBJECTS Table

The first step is to use the built-in DBA_OBJECTS table in Oracle to identify any unused objects in your database. This table contains information about all the objects in your database, including their size and status. You can use SQL queries to filter this data and find objects that have not been accessed for a certain period of time or objects that are no longer needed by your application.

Here’s an example query:

<h2>SELECT *</h2>
<h2>FROM dba_objects</h2>
<h2>WHERE owner  'your_schema_name' AND</h2> last_used < to_date('2021-07-01', 'YYYY-MM-DD')
<h2>ORDER BY size DESC;</h2>

In this query, replace "your_schema_name" with the name of the schema where you want to search for unused objects. The last_used column contains the date and time when the object was last accessed. By setting a cutoff date (in this case, July 1st, 2021), you can identify any objects that have not been used since then.

Step 2: Use the DBMS_DEPENDENCY table

Another useful table to check for unused objects is the DBMS_DEPENDENCY table. This table contains information about the dependencies between your database objects, including tables, views, procedures, and functions. If you remove an object that has dependencies, it can cause issues with other objects in your database. By checking the DBMS_DEPENDENCY table, you can identify any objects that have dependencies and ensure that they are not removed accidentally.

Here’s an example query:

<h2>SELECT obj1.name</h2> <h2>AS obj1_name, obj2.name AS obj2_name</h2>
<h2>FROM dba_objects</h2> obj1
INNER JOIN dbms_dependency dep ON obj1.object_id  dep.referenced_object_id
LEFT JOIN dba_objects obj2 ON obj2.object_id  dep.referencing_object_id AND obj1.schema_name <> obj2.schema_name;

In this query, we join the DBA_OBJECTS table with the DBMS_DEPENDENCY table to find any objects that have dependencies on other objects in your database. The result set shows the names of both objects and their schemas. If you see a dependency between two objects, it means that removing one object could cause issues with the other object.

Step 3: Use the Purge Objects Function

Once you’ve identified any unused objects in your database, you can use the Purge Objects function to remove them automatically. This function removes all the dependent objects as well and can save you a lot of time and effort compared to manually removing each object one by one.

<h2>EXECUTE dbms_purgemanager.purge_objects();</h2>

Make sure to run this function at a time when your database is not in use and back up your data before running it.

Conclusion:

In this article, we discussed how to find unused objects in an Oracle database and how to remove them to free up valuable storage space. By using the DBA_OBJECTS and DBMS_DEPENDENCY tables, you can easily identify any objects that are no longer needed by your application or users.