Calculating MySQL Database Size

Calculating the size of a MySQL database is an essential task for database administrators and developers. It helps in monitoring storage usage, planning disk space allocation, and optimizing database performance. In this tutorial, we will explore how to calculate the size of a MySQL database using SQL queries and other methods.

Using Information Schema

The information_schema database in MySQL provides metadata about all databases on the server. We can use the TABLES table in information_schema to get the total size of each database.

To get the size of all databases, you can run the following query:

SELECT 
  table_schema AS "Database", 
  SUM(data_length + index_length) / 1024 / 1024 AS "Size (MB)"
FROM 
  information_schema.TABLES
GROUP BY 
  table_schema;

This query will return a list of all databases on the server along with their total size in megabytes.

If you want to get the size of a specific database, you can add a WHERE clause to filter by table_schema:

SELECT 
  SUM(data_length + index_length) / 1024 / 1024 AS "Size (MB)"
FROM 
  information_schema.TABLES
WHERE 
  table_schema = 'v3';

Replace 'v3' with the name of your database.

To get the size in gigabytes, simply add another division by 1024:

SELECT 
  SUM(data_length + index_length) / 1024 / 1024 / 1024 AS "Size (GB)"
FROM 
  information_schema.TABLES
WHERE 
  table_schema = 'v3';

Using phpMyAdmin

If you are using phpMyAdmin to manage your MySQL databases, you can also check the database size from the interface. Navigate to the Structure tab of your database, and look for the total size displayed in the footer.

Note that this method may not provide an exact match with the query-based approach, as it calculates the size based on the sum of table sizes. However, it should give you a close approximation.

Checking File System Size (MyISAM)

For MyISAM tables, you can estimate the database size by checking the combined size of the .MYD, .MYI, and .FRM files in the data directory. For example:

du -h /var/lib/mysql/v3/*.MYD
du -h /var/lib/mysql/v3/*.MYI
du -h /var/lib/mysql/v3/*.FRM

Replace /var/lib/mysql/v3/ with the actual path to your database files.

Checking File System Size (InnoDB)

For InnoDB tables, you can estimate the database size by checking the combined size of the .IDB and .FRM files in the data directory. For example:

du -h /var/lib/mysql/v3/*.IDB
du -h /var/lib/mysql/v3/*.FRM

Replace /var/lib/mysql/v3/ with the actual path to your database files.

In conclusion, calculating the size of a MySQL database can be done using SQL queries, phpMyAdmin, or by checking file system sizes. The method you choose depends on your specific needs and preferences.