killing a query safely

Hi,

many a times the backend are stubborn. A backend is currently
executing a Query , the query usually finishes quickly < 5 secs.

But this query is on for past many minutes. I want to debug why
it is hung if it is hung.

I have also tried to kill this query using following methods:

SQL> SELECT  pg_cancel_backend(27649); # does not kill

# kill 27649                           # does not kill
# kill -TERM 27649                     # does not kill

# ps auxwww| grep  27649
postgres 27649  0.0  1.9 421060 81576 ?      S    10:41   0:00 postgres: tradein tradein_clients 216.247.238.131(59261) SELECT


this query does not block any other

tradein_clients=# SELECT * from blockers;
+---------+---------+
| blocker | blockee |
+---------+---------+
+---------+---------+
(0 rows)

\d blockers
     View "public.blockers"
+---------+---------+-----------+
| Column  |  Type   | Modifiers |
+---------+---------+-----------+
| blocker | integer |           |
| blockee | integer |           |
+---------+---------+-----------+
View definition:(Courtesy: Tom Lane)
 SELECT h.pid AS blocker, w.pid AS blockee
   FROM ONLY pg_locks h, ONLY pg_locks w
  WHERE h."granted" AND NOT w."granted" AND (h.relation = w.relation AND h."database" = w."database" OR h."transaction" = w."transaction");


Can anyone please guide what should be done in such situations.

Regds
mallah.

-- 

Best Regards,



regds
Mallah.

Rajesh Kumar Mallah
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