Knowing who is blocking a query

Once you have found out that a query is blocked, you need to know who or what is blocking them.

Getting ready

If you are logged in as a superuser you will have full access to monitoring information.

How to do it...

1. You can write the following query:

SELECT datname
, usename
, wait_event_type
, wait_event
, pg_blocking_pids(pid) AS blocked_by
, query
FROM pg_stat_activity
WHERE wait_event_type IS NOT NULL
AND wait_event_type NOT IN ('Activity', 'Client');

2. You will get an output like the following:

-[ RECORD 1 ]---+-------...