Determining The Sizes Of Tables For MySQL

To determine the sizes of your tables, including data and indexes, you can query the database when using the InnoDB storage engine in a MySQL information_schema database. It information_schema provides metadata about other databases and their structures.

Here’s how you can retrieve and sort the sizes of your tables:

1. Retrieve Table Sizes:

Use the following query to get the sizes of tables in terms of data and indexes:

SELECT 
    table_schema AS 'Database',
    table_name AS 'Table',
    ROUND(data_length / (1024 * 1024), 2) AS 'Data Size (MB)',
    ROUND(index_length / (1024 * 1024), 2) AS 'Index Size (MB)',
    ROUND((data_length + index_length) / (1024 * 1024), 2) AS 'Total Size (MB)'
FROM 
    information_schema.TABLES
WHERE 
    table_schema = 'your_database_name'  -- Replace with your database name
ORDER BY 
    (data_length + index_length) DESC;   -- This will sort by total size in descending order

2. Sorting:

In the above query, the ORDER BY clause sorts the results by the total size of each table (data + index) in descending order. You can adjust the clause accordingly if you want to sort by date or index size specifically.

For example:

• To sort by data size: ORDER BY data_length DESC
• To sort by index size: ORDER BY index_length DESC

Notes:

• The sizes are approximate, especially for InnoDB tables, due to how InnoDB storage works with MVCC (Multi-Version Concurrency Control) and other factors.
• Ensure you replace 'your_database_name' it with the actual name of your database.
• You can remove the clause if you want to see the sizes for all databases. However, be cautious; this might return many rows if you have many databases and tables.

Executing the above query in your MySQL client or tool (like MySQL Workbench) will give you a clear view of the sizes of your tables, helping you manage and optimize your database storage.

Table Inspection, Maintenance In MySQL