test.sql

application/sql

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drop table if exists t;
create table t (a text);
insert into t select md5(i::text) from generate_series(1,100000) s(i);
create index on t (a);
vacuum analyze t;

set parallel_setup_cost = 0;
set parallel_tuple_cost = 0;
set enable_indexscan = off;
set enable_seqscan = off;
set enable_mergejoin = off;
set enable_hashjoin = off;
set parallel_leader_participation = off;

alter table t set (parallel_workers = 2);

explain (analyze, verbose) select * from t t1 join t t2 using (a) where t1.a < 'a' and t2.a < 'a';