It seems that postgres with enabled row level security on a table cannot properly optimize queries. The following example sql demonstrates the issue:

begin transaction;
    create table entries (id int primary key);

    alter table entries enable row level security;
    create policy entries_policy on entries for all using (
        current_setting('app.can_read_entries')::boolean = true
    );

    create role authenticated;
    grant usage on schema public to authenticated;
    grant select on all tables in schema public to authenticated;

    set local app.can_read_entries = true;

    explain
    select * from entries
    where (
        current_setting('app.can_read_entries')::boolean = true
    );

    set local role 'authenticated';

    explain
    select * from entries;
rollback;

The execution plan as superadmin will be

Result  (cost=0.01..35.51 rows=2550 width=4)
  One-Time Filter: (current_setting('app.can_read_entries'::text))::boolean
  ->  Seq Scan on entries  (cost=0.01..35.51 rows=2550 width=4)

whereas with row level security it will be

Seq Scan on entries  (cost=0.00..54.63 rows=1275 width=4)
  Filter: (current_setting('app.can_read_entries'::text))::boolean

I already read about the leakproof attribute on functions and tried setting the leakproof attribute on current_setting and even went and tried update pg_proc set proleakproof = true;.

However, no matter what I try, postgres will not properly optimize the query with row level security.