postgresql list and order tables by size

select table_name, pg_relation_size(quote_ident(table_name))from information_schema.tableswhere 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.tablesorder by 3

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

List of all object size functions in the manual.

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_sizeFROM (       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     ) tWHERE 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

This will be more clear.

pg_size_pretty(<numeric_value>) - converts no.of bytes to human-readable format.

pg_database_size(<db_name>) - gets database size in bytes.

pg_total_relation_size(<relation_name>) - gets total size of table and its index in bytes.

pg_relation_size(<relation_name>) - gets relation (table/index) size in bytes.

pg_index_size(<relation_name>) - gets index size of the relation in bytes.

current_database() - gets the currently used database on which this query is being performed.

Query:

select current_database() as database,       pg_size_pretty(total_database_size) as total_database_size,       schema_name,       table_name,       pg_size_pretty(total_table_size) as total_table_size,       pg_size_pretty(table_size) as table_size,       pg_size_pretty(index_size) as index_size       from ( select table_name,                table_schema as schema_name,                pg_database_size(current_database()) as total_database_size,                pg_total_relation_size(table_name) as total_table_size,                pg_relation_size(table_name) as table_size,                pg_indexes_size(table_name) as index_size                from information_schema.tables                where table_schema=current_schema() and table_name like 'table_%'                order by total_table_size            ) as sizes;

Result:

 database  | total_database_size | schema_name | table_name | total_table_size | table_size | index_size-----------+---------------------+-------------+------------+------------------+------------+------------ vigneshdb | 1586 MB             | corpdata    | table_aaa  | 16 kB            | 0 bytes    | 8192 bytes vigneshdb | 1586 MB             | corpdata    | table_bbb  | 24 kB            | 0 bytes    | 16 kB vigneshdb | 1586 MB             | corpdata    | table_ccc  | 640 kB           | 112 kB     | 488 kB vigneshdb | 1586 MB             | corpdata    | table_ddd  | 9760 kB          | 3152 kB    | 6568 kB vigneshdb | 1586 MB             | corpdata    | table_eee  | 1120 MB          | 311 MB     | 808 MB

The humanized format is represent in bytes, kB, MB, GB, and TB.

bytes to kB - begins from 10240 bytes

bytes to MB - begins from 10485248 bytes = 10239.5 kB ~ 10 MB

bytes to GB - begins from 10736893952 bytes = 10239.5 MB ~ 10 BG

bytes to TB - begins from 10994579406848 bytes = 10239.5 GB ~ 10 TB

All unit conversions starts from 10 + <unit>.

For reference - Postgres Official Documentation