postgresql list and order tables by size

Question

How can I list all the tables of a PostgreSQL database and order them by size?

Answer 1

I like following statement:

SELECT 
  table_name, 
  pg_size_pretty( pg_total_relation_size(quote_ident(table_name))), 
  pg_total_relation_size(quote_ident(table_name))
FROM 
  information_schema.tables
WHERE 
  table_schema = 'public'
ORDER BY 
  pg_total_relation_size(quote_ident(table_name)) DESC

You can see total size in a pretty format, but it id ordered correctly too.

Answer 2

select table_name, pg_relation_size(quote_ident(table_name))
from information_schema.tables
where table_schema = 'public'
order by 2

This shows you the size of all tables in the schema public if you have multiple schemas, you might want to use:

select table_schema, table_name, pg_relation_size('"'||table_schema||'"."'||table_name||'"')
from information_schema.tables
order by 3

SQLFiddle example: http://sqlfiddle.com/#!15/13157/3

List of all object size functions in the manual.

Answer 3

This will show you the schema name, table name, size pretty and size (needed for sort).

SELECT
  schema_name,
  relname,
  pg_size_pretty(table_size) AS size,
  table_size

FROM (
       SELECT
         pg_catalog.pg_namespace.nspname           AS schema_name,
         relname,
         pg_relation_size(pg_catalog.pg_class.oid) AS table_size

       FROM pg_catalog.pg_class
         JOIN pg_catalog.pg_namespace ON relnamespace = pg_catalog.pg_namespace.oid
     ) t
WHERE schema_name NOT LIKE 'pg_%'
ORDER BY table_size DESC;

I build this based on the solutions from here list of schema with sizes (relative and absolute) in a PostgreSQL database