Extensions, PostGIS, Full Text Search Dictionaries, Data Caching, and Tuning - Learning Heroku Postgres - page 188

Row locking - pgrowlocks
This extension provides a function called pgrowlocks to display locked rows in a specif-
ic table.
First, you must install the extension:
$ heroku pg:psql --app your-app-name
CREATE EXTENSION pgrowlocks;
The pgrowlocks function accepts a parameter that is the table name. For example:
SELECT * FROM pgrowlocks('users');
locked_row| lock_type | locker | multi | xids |
pids
----------+-----------+--------+-------+-----------+---------
(0,1) | Shared | 22 | t | {378,809} | {23457}
(0,2) | Exclusive | 345 | f | {780} | {12869}
For details, visit the documentation at http://www.postgresql.org/docs/current/static/pgrow-
locks.html .