​
Overview

The pg_total_relation_size() is a database object size function that retrieves the size of a table and is useful for monitoring the storage requirements.

​
Syntax

The syntax for the pg_total_relation_size() function is as follows: 
pg_total_relation_size('relation_name');
It returns the size of the specified table in bytes.

​
Parameters

The following parameters are required to execute this function:
  • relation_name: name of the table for which you want to determine the size

​
Example

For the needs of this section, we will create a users table 
CREATE TABLE users (
    username TEXT,
    email TEXT
);
INSERT INTO users (username, email) VALUES
    ('john_doe', '[email protected]'),
    ('jane_smith', '[email protected]'),
    ('alice_smith', '[email protected]'),
    ('bob_jones', '[email protected]'),
    ('susan_wilson', '[email protected]'),
    ('michael_jackson', '[email protected]'),
    ('lisa_johnson', '[email protected]'),
    ('david_smith', '[email protected]');
Now we would like to use the pg_total_relation_size() function to determine the size of the users table (in bytes) 
SELECT pg_total_relation_size('users');
By executing the query above, we will get the following output: 
 pg_total_relation_size 
------------------------
                    556