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How to Get the Size Of A Materialized View In Oracle?

4 minutes read

To get the size of a materialized view in Oracle, you can use the DBA_MVIEWS or ALL_MVIEWS dictionary views. These views contain information about the materialized views defined in the database, including their size. By querying these views and selecting the appropriate columns, such as BYTES, you can determine the size of a specific materialized view. Additionally, you can use the DBA_SEGMENTS view to get information about the segments associated with the materialized view, which can also help you determine its size.


How to estimate the storage requirements for a materialized view in Oracle based on its query complexity?

Estimating the storage requirements for a materialized view in Oracle based on its query complexity can be a complex task, but there are some general guidelines that can help you get a rough estimate. Here are some steps to follow:

  1. Understand the query complexity: Take a close look at the SQL query that defines the materialized view. Note the number of tables involved, the number of columns being selected, the number of joins, any aggregation functions, and any subqueries or complex conditions.
  2. Estimate the size of the result set: Try to estimate the number of rows that would be returned by the query when it is executed against the underlying tables. This will give you an idea of the amount of data that will need to be stored in the materialized view.
  3. Consider the data types: Look at the data types of the columns in the result set, as this will affect the amount of storage required. For example, a materialized view that contains large text or blob columns will require more storage than one that only contains integer or date columns.
  4. Factor in any indexes: If the materialized view includes indexes, you will need to account for the additional storage required for these indexes. Consider the number and types of indexes that are defined on the materialized view columns.
  5. Add a buffer for growth: It is always a good idea to add a buffer for potential growth in the data over time. You can estimate this based on historical data growth trends or anticipated increases in data volume.


Overall, estimating the storage requirements for a materialized view can be a complex task that may require trial and error. It is a good idea to monitor the actual storage usage of the materialized view after it has been created and adjust as needed. Additionally, consulting with a database administrator or Oracle performance tuning expert can also provide valuable insights and guidance.


What is the best way to determine the size of a materialized view in Oracle?

One way to determine the size of a materialized view in Oracle is to query the USER_MVIEWS and ALL_MVIEWS data dictionary views.


You can use the following SQL query to get the size of a materialized view in Oracle:

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SELECT mview_name, ROUND(ROUND((data_length + last_analyzed)/1024/1024,2),2) AS size_in_MB 
FROM user_mviews 
WHERE mview_name = 'your_materialized_view_name';


This query will give you the size of the materialized view in megabytes. You can adjust the query to query ALL_MVIEWS if you need to get information about materialized views in all schemas.


What is the role of the DBA_DATA_FILES view in determining the size of a materialized view in Oracle?

The DBA_DATA_FILES view in Oracle provides information about the physical data files that make up a database. By querying this view, a database administrator can determine the size of the data files that store the materialized view data. This information can be used to calculate the total size of the materialized view and monitor its growth over time.


Additionally, the DBA_DATA_FILES view can help identify any issues related to storage space or performance of materialized views. By monitoring the size of data files, a DBA can proactively address any potential problems before they impact the performance of the materialized view.


Overall, the DBA_DATA_FILES view plays a crucial role in managing and optimizing the size of materialized views in Oracle databases.


What are some factors that contribute to the size of a materialized view in Oracle?

  1. Number of rows in the underlying tables: The more rows in the underlying tables, the larger the materialized view will be.
  2. Complexity of the query: Materialized views that require complex joins, aggregations, or calculations will typically be larger in size.
  3. Number and size of columns selected: Materialized views that select a large number of columns, or columns with large data types (such as LONG, CLOB, or BLOB) will be larger in size.
  4. Refresh method: Materialized views can be set to refresh on-demand, on a schedule, or on commit. The refresh method can impact the size of the materialized view.
  5. Compression settings: Oracle offers different compression methods for materialized views, which can impact the size of the view.
  6. Indexes: Materialized views can have indexes, which can impact the overall size of the materialized view.
  7. Materialized view logs: If materialized view logs are enabled on the underlying tables, this can impact the size of the materialized view.
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