Re: Alter table never finishes

On Tue, Jul 30, 2013 at 10:07 AM, Leonardo M. Ramé <l(dot)rame(at)griensu(dot)com>wrote:

>
> select pg_cancel_backend(pid) from pg_stat_activity where pid <>
> pg_backend_pid();
>
> And it returned this:
>
> pg_cancel_backend
> -------------------
> t
> t
> (2 rows)
>
> But when I execute my update table command, it still never ends...Any
> hint?.
>
>
Sounds like locking issues. In another session -- other than the one you
are trying to run your update, what does the following query show?

SELECT
waiting.locktype AS waiting_locktype,
waiting.relation::regclass AS waiting_table,
waiting_stm.query AS waiting_query,
waiting.mode AS waiting_mode,
waiting.pid AS waiting_pid,
other.locktype AS other_locktype,
other.relation::regclass AS other_table,
other_stm.query AS other_query,
other.mode AS other_mode,
other.pid AS other_pid,
other.granted AS other_granted
FROM pg_catalog.pg_locks AS waiting
JOIN pg_catalog.pg_stat_activity AS waiting_stm ON (waiting_stm.pid =
waiting.pid)
JOIN pg_catalog.pg_locks AS other ON ((waiting."database" =
other."database" AND waiting.relation = other.relation) OR
waiting.transactionid = other.transactionid)
JOIN pg_catalog.pg_stat_activity AS other_stm ON (other_stm.pid = other.pid)
WHERE NOT waiting.granted
AND waiting.pid <> other.pid;