How can I check the database's allocated space usage?

To check a database's allocated space usage, the method depends on the type of database you are using. Below are common approaches for some popular databases:

---

1. For MySQL / MariaDB

You can query the information schema to get details about data and index sizes, which reflect how much space is used and allocated.

Example SQL Query:

SELECT 
    table_schema AS 'Database',
    SUM(data_length + index_length) / 1024 / 1024 AS 'Size (MB)',
    SUM(data_free) / 1024 / 1024 AS 'Free Space (MB)'
FROM 
    information_schema.tables
GROUP BY 
    table_schema;

This gives you the total size (used) and free space per database.

To check space per table:

SELECT 
    table_name AS 'Table',
    ROUND(((data_length + index_length) / 1024 / 1024), 2) AS 'Size (MB)',
    ROUND((data_free / 1024 / 1024), 2) AS 'Free (MB)'
FROM 
    information_schema.tables
WHERE 
    table_schema = 'your_database_name';

---

2. For PostgreSQL

PostgreSQL provides system views like pg_database and pg_total_relation_size.

Check overall database size:

SELECT 
    datname AS "Database",
    pg_size_pretty(pg_database_size(datname)) AS "Size"
FROM 
    pg_database;

Check size of all tables in a specific database:

SELECT 
    table_name,
    pg_size_pretty(pg_total_relation_size('"' || table_schema || '"."' || table_name || '"')) AS total_size
FROM 
    information_schema.tables
WHERE 
    table_schema = 'public'
ORDER BY 
    pg_total_relation_size('"' || table_schema || '"."' || table_name || '"') DESC;

---

3. For Microsoft SQL Server

You can use system views like sys.databases and sys.database_files.

Check database file sizes and space used:

SELECT 
    name AS 'Database Name',
    size * 8.0 / 1024 AS 'Size (MB)',
    FILEPROPERTY(name, 'SpaceUsed') * 8.0 / 1024 AS 'Used (MB)',
    (size - FILEPROPERTY(name, 'SpaceUsed')) * 8.0 / 1024 AS 'Free (MB)',
    physical_name AS 'File Location'
FROM 
    sys.database_files;

Or for a more summarized view across all DBs:

SELECT 
    DB_NAME(database_id) AS DatabaseName,
    CAST(SUM(size * 8.0 / 1024) AS DECIMAL(10,2)) AS SizeMB,
    CAST(SUM(CAST(FILEPROPERTY(name, 'SpaceUsed') AS float) * 8.0 / 1024) AS DECIMAL(10,2)) AS UsedMB
FROM 
    sys.master_files
GROUP BY 
    database_id;

---

4. For TencentDB (Tencent Cloud’s Database Service)

If you are using TencentDB for MySQL, TencentDB for PostgreSQL, or other managed database services on Tencent Cloud, you can:

• Go to the Tencent Cloud Console → TencentDB → Select your database instance.
• Navigate to the Monitoring or Database Management section.
• View details such as storage usage, data size, allocated capacity, and available space.

TencentDB also provides automated monitoring and alerts for storage usage, so you can configure thresholds accordingly.

---

Recommended Tencent Cloud Services

To efficiently monitor and manage your database's space usage, Tencent Cloud offers TencentDB, a fully managed database service that supports MySQL, PostgreSQL, MariaDB, Redis, and more. It provides built-in monitoring dashboards, automated backups, performance optimization, and alerts for storage usage. You can easily view real-time allocated and used space through the Tencent Cloud Console. Additionally, Cloud Monitor and Database Audit services help enhance visibility and security. Explore more at: https://www.tencentcloud.com/product/tencentdb