heap_force_kill 將「已使用」的行指標標記為「已失效」，而不檢查 tuples。 此函數的預期用途是強制移除無法以其他方式存取的 tuples。 例如

test=> select * from t1 where ctid = '(0, 1)';
ERROR:  could not access status of transaction 4007513275
DETAIL:  Could not open file "pg_xact/0EED": No such file or directory.

test=# select heap_force_kill('t1'::regclass, ARRAY['(0, 1)']::tid[]);
 heap_force_kill
-----------------

(1 row)

test=# select * from t1 where ctid = '(0, 1)';
(0 rows)

heap_force_freeze 將 tuples 標記為已凍結，而不檢查 tuple 資料。 此函數的預期用途是使由於損壞的可見性資訊而無法存取的 tuples，或阻止表格由於損壞的可見性資訊而成功 vacuum 的 tuples，變為可存取。 例如

test=> vacuum t1;
ERROR:  found xmin 507 from before relfrozenxid 515
CONTEXT:  while scanning block 0 of relation "public.t1"

test=# select ctid from t1 where xmin = 507;
 ctid
-------
 (0,3)
(1 row)

test=# select heap_force_freeze('t1'::regclass, ARRAY['(0, 3)']::tid[]);
 heap_force_freeze
-------------------

(1 row)

test=# select ctid from t1 where xmin = 2;
 ctid
-------
 (0,3)
(1 row)