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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