Postgres tablespace size is bigger than database size PostgreSQL tablespace size is bigger than database size. What is the problem about that?

SELECT pg_size_pretty(pg_database_size('ibidev'));
 pg_size_pretty 
----------------
 2578 MB
(1 row)

SELECT pg_size_pretty(pg_tablespace_size('tbs_ibi_dat'));
 pg_size_pretty 
----------------
 47 GB
(1 row)


Using PostgreSQL 9.1
A tablespace can contain tables from more than one database.

The extra space must be from another database.