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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.

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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.

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Parameters

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

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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', 'john.doe@example.com'),
    ('jane_smith', 'jane.smith@example.com'),
    ('alice_smith', 'alice.smith@example.com'),
    ('bob_jones', 'bob.jones@example.com'),
    ('susan_wilson', 'susan.wilson@example.com'),
    ('michael_jackson', 'michael.jackson@example.com'),
    ('lisa_johnson', 'lisa.johnson@example.com'),
    ('david_smith', 'david.smith@example.com');
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