Re: weird long time query

Kaijiang Chen <chenkaijiang@gmail.com> writes:
> I'm using postgres 9.4.17 on centos 7.
> I check the running queries with the following SQL:
> SELECT
>     procpid,
>     start,
>     now() - start AS lap,
>     current_query
> FROM
>     (SELECT
>         backendid,
>         pg_stat_get_backend_pid(S.backendid) AS procpid,
>         pg_stat_get_backend_activity_start(S.backendid) AS start,
>         pg_stat_get_backend_activity(S.backendid) AS current_query
>     FROM
>         (SELECT pg_stat_get_backend_idset() AS backendid) AS S
>     ) AS S
> WHERE
>     current_query <> '<IDLE>'
> ORDER BY
>     lap DESC;

Don't know where you got this query from, but it's wrong for any PG
version more recent than (I think) 9.1.  We don't use "<IDLE>" as an
indicator of idle sessions anymore; rather, those can be identified
by having state = 'idle'.  What's in the query column for such a session
is its last query.

> Then, I found a SQL that has run for some days (and still running):
> procpid       | 32638
> start         | 2019-11-25 16:29:29.529318+08
> lap           | 21 days 18:24:54.707369
> current_query | DEALLOCATE pdo_stmt_00000388

It's not running.  That was the last query it ran, back in November :-(
You could zap the session with pg_terminate_backend(), but
pg_cancel_backend() is not going to have any effect because there's
no active query.

                        regards, tom lane