ctid는 typle id로 물리적 위치를 나타내는데 update 하면 바뀐다고 한다(oracle 등은 고정된 순서로 유지되는 듯)

[링크 : https://www.postgresdba.com/bbs/board.php?bo_table=B12&wr_id=63]

 

ctid

The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly, a row's ctid will change each time it is updated or moved by VACUUM FULL. Therefore ctid is useless as a long-term row identifier. The OID, or even better a user-defined serial number, should be used to identify logical rows.

[링크 : https://www.postgresql.org/docs/8.2/ddl-system-columns.html]

Posted by 구차니