Row-Level Security Policy

-- Create users alice, bob, and peter.
gaussdb=# CREATE USER alice PASSWORD '********';
gaussdb=# CREATE USER bob PASSWORD '********';
gaussdb=# CREATE USER peter PASSWORD '********';

-- Create the all_data table that contains user information.
gaussdb=# CREATE TABLE all_data(id int, role varchar(100), data varchar(100));

-- Insert data into the data table.
gaussdb=# INSERT INTO all_data VALUES(1, 'alice', 'alice data');
gaussdb=# INSERT INTO all_data VALUES(2, 'bob', 'bob data');
gaussdb=# INSERT INTO all_data VALUES(3, 'peter', 'peter data');

-- Grant the read permission for the all_data table to users alice, bob, and peter.
gaussdb=# GRANT SELECT ON all_data TO alice, bob, peter;

-- Enable row-level security policy.
gaussdb=# ALTER TABLE all_data ENABLE ROW LEVEL SECURITY;

-- Create a row-level security policy to specify that the current user can view only their own data.
gaussdb=# CREATE ROW LEVEL SECURITY POLICY all_data_rls ON all_data USING(role = CURRENT_USER);

-- View table details.
gaussdb=# \d+ all_data
                               Table "public.all_data"
 Column |          Type          | Modifiers | Storage  | Stats target | Description
--------+------------------------+-----------+----------+--------------+-------------
 id     | integer                |           | plain    |              |
 role   | character varying(100) |           | extended |              |
 data   | character varying(100) |           | extended |              |
Row Level Security Policies:
    POLICY "all_data_rls" FOR ALL
      TO public
      USING (((role)::name = "current_user"()))
Has OIDs: no
Distribute By: HASH(id)
Location Nodes: ALL DATANODES
Options: orientation=row, compression=no, enable_rowsecurity=true

-- Switch to user alice and run SELECT * FROM public.all_data.
gaussdb=# SELECT * FROM public.all_data;
 id | role  |    data
----+-------+------------
  1 | alice | alice data
(1 row)

gaussdb=# EXPLAIN(COSTS OFF) SELECT * FROM public.all_data;
                           QUERY PLAN
----------------------------------------------------------------
 Streaming (type: GATHER)
   Node/s: All datanodes
   ->  Seq Scan on all_data
         Filter: ((role)::name = 'alice'::name)
 Notice: This query is influenced by row level security feature
(5 rows)

-- Switch to user peter and run SELECT * FROM public.all_data.
gaussdb=# SELECT * FROM public.all_data;
 id | role  |    data
----+-------+------------
  3 | peter | peter data
(1 row)

gaussdb=# EXPLAIN(COSTS OFF) SELECT * FROM public.all_data;
                           QUERY PLAN
----------------------------------------------------------------
 Streaming (type: GATHER)
   Node/s: All datanodes
   ->  Seq Scan on all_data
         Filter: ((role)::name = 'peter'::name)
 Notice: This query is influenced by row level security feature
(5 rows)