BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	c_custkey,
	c_name,
	sum(l_extendedprice * (1 - l_discount)) as revenue,
	c_acctbal,
	n_name,
	c_address,
	c_phone,
	c_comment
from
	customer,
	orders,
	lineitem,
	nation
where
	c_custkey = o_custkey
	and l_orderkey = o_orderkey
	and o_orderdate >= date '1993-03-01'
	and o_orderdate < cast(date '1993-03-01' + interval '3 month' as date)
	and l_returnflag = 'R'
	and c_nationkey = n_nationkey
group by
	c_custkey,
	c_name,
	c_acctbal,
	c_phone,
	n_name,
	c_address,
	c_comment
order by
	revenue desc
LIMIT 20;
                                                                                                QUERY PLAN                                                                                                 
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=1154236.03..1154236.08 rows=20 width=175) (actual time=24800.142..24800.149 rows=20 loops=1)
   Buffers: shared hit=860335 read=561212 dirtied=395 written=9437
   ->  Sort  (cost=1154236.03..1155644.45 rows=563368 width=175) (actual time=24800.139..24800.141 rows=20 loops=1)
         Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount))))
         Sort Method: top-N heapsort  Memory: 30kB
         Buffers: shared hit=860335 read=561212 dirtied=395 written=9437
         ->  HashAggregate  (cost=1133611.33..1139245.01 rows=563368 width=175) (actual time=24437.887..24661.216 rows=381982 loops=1)
               Group Key: customer.c_custkey, customer.c_name, customer.c_acctbal, customer.c_phone, nation.n_name, customer.c_address, customer.c_comment
               Buffers: shared hit=860332 read=561212 dirtied=395 written=9437
               ->  Hash Join  (cost=352036.14..1119527.13 rows=563368 width=175) (actual time=3877.815..22097.909 rows=1148250 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=860332 read=561212 dirtied=395 written=9437
                     ->  Hash Join  (cost=352034.58..1111779.25 rows=563368 width=153) (actual time=3877.764..21696.264 rows=1148250 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=860331 read=561212 dirtied=395 written=9437
                           ->  Hash Join  (cost=283006.58..1034300.73 rows=563368 width=12) (actual time=2303.199..19308.726 rows=1148250 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=825664 read=560601 dirtied=395 written=9437
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..689705.53 rows=14921434 width=12) (actual time=0.069..13505.039 rows=14808293 loops=1)
                                       Buffers: shared hit=637258 read=517777 dirtied=395 written=9408
                                 ->  Hash  (cost=275877.43..275877.43 rows=570297 width=8) (actual time=2296.534..2296.534 rows=573422 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30592kB
                                       Buffers: shared hit=188406 read=42824 written=29
                                       ->  Bitmap Heap Scan on orders  (cost=12281.98..275877.43 rows=570297 width=8) (actual time=291.498..2102.408 rows=573422 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                             Heap Blocks: exact=229599
                                             Buffers: shared hit=188406 read=42824 written=29
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12139.41 rows=570297 width=0) (actual time=211.092..211.092 rows=577345 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-03-01'::date) AND (o_orderdate < '1993-06-01'::date))
                                                   Buffers: shared read=1631 written=5
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1554.555..1554.555 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=34667 read=611
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.022..657.852 rows=1500000 loops=1)
                                       Buffers: shared hit=34667 read=611
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.030..0.030 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 10kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.009..0.014 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.543 ms
 Execution time: 25221.408 ms
(42 rows)

COMMIT;
COMMIT