Consider the following table, created on a specific tablespace:

```sql
CREATE TABLE example (
    example_id int4 NOT NULL,
    name VARCHAR(12) NOT NULL,
    CONSTRAINT example_pkey 
       PRIMARY KEY (example_id)
) TABLESPACE tbspc01;

Accessing pg_class and pg_tablespace one may verify the good result:

SELECT c.relname, 
       t.spcname
  FROM pg_class c 
  JOIN pg_tablespace t 
    ON c.reltablespace = t.oid 
 WHERE c.relname LIKE '%example%';

Producing:

 relname |   spcname
---------+-------------
 example | chinook_spc
(1 row)

However, as the table grows in size, there will be mismatch between the table size reported by pg_total_relation_size() and that reported by pg_tablespace_size(), the table being larger than the tablespace.

That is so for the primary key is stored in the default tablespace:

SELECT indexname, 
       tablespace
  FROM pg_indexes 
 WHERE indexname LIKE '%example%';

Result:

  indexname   | tablespace
--------------+------------
 example_pkey |
(1 row)

It is possible to move the primary key to the desired index with ALTER INDEX [...] SET TABLESPACE. But why isn't it stored in the same tablespace as the table? And is there a way to force it there in CREATE TABLE instruction?