-- test parallel bitmap heap scan.

set enable_seqscan to off;

set enable_indexscan to off;

set enable_hashjoin to off;

set enable_mergejoin to off;

set enable_material to off;

set effective_io_concurrency=50;

set work_mem='64kB'; --set small work mem to force lossy pages

explain (costs off)

selectcount((unique1)) from tenk1where hundred > 1;

select count(*) from tenk1, tenk2wheretenk1.hundred > 1 and tenk2.thousand=0;

QUERY PLAN

------------------------------------------------------------

Finalize Aggregate

-> Gather

Workers Planned: 4

-> Partial Aggregate

Aggregate

-> Nested Loop

-> Seq Scan on tenk2

Filter: (thousand = 0)

-> Gather

Workers Planned: 4

-> Parallel Bitmap Heap Scan on tenk1

Recheck Cond: (hundred > 1)

-> Bitmap Index Scan on tenk1_hundred

Index Cond: (hundred > 1)

(8 rows)

(10 rows)

select count(*) from tenk1, tenk2 where tenk1.hundred > 1 and tenk2.thousand=0;

count

-------

98000

(1 row)

create table bmscantest (a int, t text);

insert into bmscantest select r, 'fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo' FROM generate_series(1,100000) r;

create index i_bmtest ON bmscantest(a);

select count(*) from bmscantest where a>1;

count

-------

99999

(1 row)

reset enable_seqscan;

reset enable_indexscan;

reset enable_hashjoin;

reset enable_mergejoin;

reset enable_material;

reset effective_io_concurrency;

reset work_mem;

drop table bmscantest;

-- test parallel merge join path.

set enable_hashjoin to off;

set enable_nestloop to off;

set enable_seqscan to off;

set enable_indexscan to off;

set enable_hashjoin to off;

set enable_mergejoin to off;

set enable_material to off;

set effective_io_concurrency=50;

set work_mem='64kB';--set small work mem to force lossy pages

explain (costs off)

selectcount((unique1))from tenk1where hundred>1;

selectcount(*)from tenk1, tenk2wheretenk1.hundred>1andtenk2.thousand=0;

selectcount(*)from tenk1, tenk2wheretenk1.hundred>1andtenk2.thousand=0;

createtablebmscantest (aint, ttext);

insert into bmscantestselect r,'fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo'FROM generate_series(1,100000) r;

createindexi_bmtestON bmscantest(a);

selectcount(*)from bmscantestwhere a>1;

reset enable_seqscan;

reset enable_indexscan;

reset enable_hashjoin;

reset enable_mergejoin;

reset enable_material;

reset effective_io_concurrency;

reset work_mem;

droptable bmscantest;

set enable_hashjoin to off;