Table 9-73. Database Object Size Functions

Name Return Type Description
pg_column_size(any) int Number of bytes used to store a particular value (possibly compressed)
pg_database_size(oid) bigint Disk space used by the database with the specified OID
pg_database_size(name) bigint Disk space used by the database with the specified name
pg_indexes_size(regclass) bigint Total disk space used by indexes attached to the specified table
pg_relation_size(relation regclass, fork text) bigint Disk space used by the specified fork ('main', 'fsm', 'vm', or 'init') of the specified table or index
pg_relation_size(relation regclass) bigint Shorthand for pg_relation_size(..., 'main')
pg_size_pretty(bigint) text Converts a size in bytes expressed as a 64-bit integer into a human-readable format with size units
pg_size_pretty(numeric) text Converts a size in bytes expressed as a numeric value into a human-readable format with size units
pg_table_size(regclass) bigint Disk space used by the specified table, excluding indexes (but including TOAST, free space map, and visibility map)
pg_tablespace_size(oid) bigint Disk space used by the tablespace with the specified OID
pg_tablespace_size(name) bigint Disk space used by the tablespace with the specified name
pg_total_relation_size(regclass) bigint Total disk space used by the specified table, including all indexes and TOAST data

所以，比如要查看 test 数据库的大小，则输入：

select pg_size_pretty(pg_database_size('test'));