-- -- PARALLEL -- create or replace function parallel_restricted(int) returns int as $$begin return $1; end$$ language plpgsql parallel restricted; -- Serializable isolation would disable parallel query, so explicitly use an -- arbitrary other level. begin isolation level repeatable read; -- encourage use of parallel plans set parallel_setup_cost=0; set parallel_tuple_cost=0; set min_parallel_relation_size=0; set max_parallel_workers_per_gather=4; explain (costs off) select count(*) from a_star; select count(*) from a_star; -- test that parallel_restricted function doesn't run in worker alter table tenk1 set (parallel_workers = 4); explain (verbose, costs off) select parallel_restricted(unique1) from tenk1 where stringu1 = 'GRAAAA' order by 1; -- test parallel plan when group by expression is in target list. explain (costs off) select length(stringu1) from tenk1 group by length(stringu1); select length(stringu1) from tenk1 group by length(stringu1); explain (costs off) select stringu1, count(*) from tenk1 group by stringu1 order by stringu1; -- test that parallel plan for aggregates is not selected when -- target list contains parallel restricted clause. explain (costs off) select sum(parallel_restricted(unique1)) from tenk1 group by(parallel_restricted(unique1)); set force_parallel_mode=1; explain (costs off) select stringu1::int2 from tenk1 where unique1 = 1; -- provoke error in worker select stringu1::int2 from tenk1 where unique1 = 1; rollback;