How to get user-specific settings in PostgreSQL?

I have to collect some information of PostgreSQL roles. One piece of information is whether the role has different settings than ‘usual’, usual meaning here default values for only a few parameters (eg. log_statement).

So far I have only one idea: loop over all the users and issue the commands

c postgres username

SHOW log_statement;

and then process the output.

I am wondering whether there is a similar method like querying the pg_settings view, showing per-user settings? I don’t need to know session-specific differences, only those that are persisted.

You can get the role configuration by querying pg_catalog.pg_shadow or pg_catalog.pg_user,
as the following:

–Query pg_shadow

francs=# select usename,useconfig from pg_shadow ;
   usename    |           useconfig           
--------------+-------------------------------
 postgres     | 
 user_a       | 
 user_b       | 
 skytf_select | {"search_path=skytf, public"}
 francs       | 
 dwetl        | 
 skytf        | 
(7 rows)

francs=# alter role francs  set log_statement='all';
ALTER ROLE

francs=# select usename,useconfig from pg_shadow ;
   usename    |           useconfig           
--------------+-------------------------------
 postgres     | 
 user_a       | 
 user_b       | 
 skytf_select | {"search_path=skytf, public"}
 rancs        | {log_statement=all}
 dwetl        | 
 skytf        | 
(7 rows)

Unfortunately pg_shadow does not show roles with no LOGIN privilege.

I find it more useful to use @dezso hint view in the following query:

SELECT coalesce(role.rolname, 'database wide') as role, 
       coalesce(db.datname, 'cluster wide') as database, 
       setconfig as what_changed
FROM pg_db_role_setting role_setting
LEFT JOIN pg_roles role ON role.oid = role_setting.setrole
LEFT JOIN pg_database db ON db.oid = role_setting.setdatabase;

As always, just add it to psqlrc file (see doc)