Thread: 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.
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 +---------------------------------------------------+ | Tradeindia.com (3,97,300) Registered Users | | Indias' Leading B2B eMarketPlace | | http://www.tradeindia.com/ | +---------------------------------------------------+
Rajesh Kumar Mallah <mallah@tradeindia.com> writes:
> 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.
Attach to the backend process with gdb and get a stack trace ---
that would at least give us some information to work with.
regards, tom lane