Order PostgreSQL Tables in a Database by Disk Usage

Ever wanted to figure out which tables in your PostreSQL database are taking up the most space on the disk? It’s pretty easy to find out if you know the magic query.

First, connect to psql in the terminal via a command like:

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psql -U postgres

Next, connect to the database of interest:

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\connect my_database_name_here

Paste the following SELECT statement into terminal and press Enter:

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SELECT nspname || '.' || relname AS "relation",
  pg_size_pretty(pg_total_relation_size(C.oid)) AS "total_size"
FROM pg_class C
LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)
WHERE nspname NOT IN ('pg_catalog', 'information_schema')
AND C.relkind <> 'i'
AND nspname !~ '^pg_toast'
ORDER BY pg_total_relation_size(C.oid) DESC
LIMIT 20;

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