explain_analyze_parallel_stats_analysis.txt

create table mill (a int);
create index on mill(a);

insert into mill select x%1000 from generate_Series(1,10000000)x;
vacuum analyze mill;

create table big (a int primary key);
insert into big select x from generate_series(1,10000000)x;
create table probe (a int);
insert into probe select 1 from generate_Series(1,1000000);
analyze big,probe;

create table agg (a int, b int);
insert into agg select a%1000,a from generate_Series(1,1000000)a;
create index on agg(a);

set parallel_tuple_cost=0;
set parallel_setup_cost=0;
set enable_indexscan=0;


-- each includes "Worker N:" with stats for the operation.
explain (analyze) select * from mill where a < 100; -- Bitmap Heap Scan
explain (analyze) select * from big b inner join probe p on b.a=p.a; -- Memoize
explain (analyze) select * from probe order by a; -- Sort
set enable_nestloop=0;
explain (analyze) select a,count(b) from agg group by a; -- HashAgg ODD ONE OUT. GETS MAX DETAILS FROM WORKERS.
explain (analyze) select * from big b inner join probe p on b.a=p.a; -- Hash
reset enable_nestloop;

set enable_indexscan=1; set enable_bitmapscan=0; set enable_seqscan=0;
explain (analyze) select a,b from agg where a > 10 order by a,b; -- Incremental Sort
set enable_indexscan=0; set enable_bitmapscan=1; set enable_seqscan=1;


-- each includes "Worker N:" with stats for the operation
-- also includes actual time and rows for each worker.
explain (analyze, verbose) select * from mill where a < 100; -- Bitmap Heap Scan
explain (analyze, verbose) select * from big b inner join probe p on b.a=p.a; -- Memoize
explain (analyze, verbose) select * from probe order by a; -- Sort
set enable_nestloop=0;
explain (analyze, verbose) select a,count(b) from agg group by a; -- HashAgg ODD ONE OUT. GETS MAX DETAILS FROM WORKERS.
explain (analyze, verbose) select * from big b inner join probe p on b.a=p.a; -- Hash
reset enable_nestloop;

set enable_indexscan=1; set enable_bitmapscan=0; set enable_seqscan=0;
explain (analyze, verbose) select a,b from agg where a > 10 order by a,b; -- Incremental Sort
set enable_indexscan=0; set enable_bitmapscan=1; set enable_seqscan=1;


-- each includes "Worker N:" with stats for the operation
-- shows a single total buffers which includes leader and worker buffers.
explain (analyze, buffers) select * from mill where a < 100; -- Bitmap Heap Scan
explain (analyze, buffers) select * from big b inner join probe p on b.a=p.a; -- Memoize
explain (analyze, buffers) select * from probe order by a; -- Sort
set enable_nestloop=0;
explain (analyze, buffers) select a,count(b) from agg group by a; -- HashAgg ODD ONE OUT. GETS MAX DETAILS FROM WORKERS.
reset enable_nestloop;

set enable_indexscan=1; set enable_bitmapscan=0; set enable_seqscan=0;
explain (analyze, buffers) select a,b from agg where a > 10 order by a,b; -- Incremental Sort
set enable_indexscan=0; set enable_bitmapscan=1; set enable_seqscan=1;


-- each includes "Worker N:" with stats for the operation
-- also includes actual time and rows for each worker.
-- shows a single total buffers which includes leader and worker buffers.
-- shows buffer counts for each worker process
explain (analyze, buffers, verbose) select * from mill where a < 100; -- Bitmap Heap Scan
explain (analyze, buffers, verbose) select * from big b inner join probe p on b.a=p.a;
explain (analyze, buffers, verbose) select * from probe order by a; -- Sort
set enable_nestloop=0;
explain (analyze, buffers, verbose) select a,count(b) from agg group by a; -- HashAgg ODD ONE OUT. GETS MAX DETAILS FROM WORKERS.
reset enable_nestloop;

set enable_indexscan=1; set enable_bitmapscan=0; set enable_seqscan=0;
explain (analyze, buffers, verbose) select a,b from agg where a > 10 order by a,b; -- Incremental Sort
set enable_indexscan=0; set enable_bitmapscan=1; set enable_seqscan=1;