How to do it…

We can see the size of a table by using this command:

postgres=# select pg_relation_size('pgbench_accounts');

The output of this command is as follows:

pg_relation_size
------------------
           13582336
(1 row)

We can also see the total size of a table, including indexes and other related spaces, as follows:

postgres=# select pg_total_relation_size('pgbench_accounts');

The output is as follows:

pg_total_relation_size
------------------------
         15425536
(1 row)

We can also use a psql command, like this:

postgres=# \dt+ pgbench_accounts
                        List of relations
 Schema |       Name       | Type  | Owner  | Size  | Description
--------+------------------+-------+--------+-------+-------------
 gianni | pgbench_accounts | table | gianni | 13 MB |
(1 row)