create extension if not exists btree_gist;
--drop extension if exists btree_gist cascade;
drop table if exists test_resources;
create table test_resources (
  id serial, 
  resource_id integer not null, 
  service_id integer not null, 
  date_start timestamp without time zone not null, 
  date_end timestamp without time zone default 'infinity'::timestamp without time zone not null, 
  constraint test_resources_pkey primary key(id));

alter table test_resources  add constraint xak_test_resources_resource_id_service_id_range_date_start_date_end
    exclude using gist (resource_id with =, service_id with =, tsrange(date_start, date_end) with &&);

insert into test_resources values (default, 1,1, (now()-'1 day'::interval)::date::timestamp, (now()+'10 day'::interval)::date::timestamp);--ok
insert into test_resources values (default, 1,2, (now()-'0 day'::interval)::date::timestamp, (now()+'11 day'::interval)::date::timestamp);--ok
insert into test_resources values (default, 1,3, (now()-'0 day'::interval)::date::timestamp, (now()+'11 day'::interval)::date::timestamp);--ok
insert into test_resources values (default, 1,1, (now()-'10 day'::interval)::date::timestamp, (now()-'0 day'::interval)::date::timestamp);--error


select * from test_resources