This article describes how to find a role creation date.
In order to find out when a role had been created, issue the following SQL query:
gpadmin=# SELECT rolname,actionname,TO_CHAR(statime, 'DD-MM-YYYY HH24:MI:SS') AS "action date" from pg_roles AS r LEFT JOIN pg_stat_operations AS o ON r.oid=o.objid WHERE actionname='CREATE' AND rolname = 'gpmon'; rolname | actionname | action date ---------+------------+--------------------- gpmon | CREATE | 24-10-2016 03:18:34 (1 row)