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 '1993-11-01'
	and o_orderdate < cast(date '1993-11-01' + 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=1190468.78..1190468.83 rows=20 width=175) (actual time=95246.903..95246.912 rows=20 loops=1)
   Buffers: shared hit=601158 read=826986 dirtied=1322 written=86
   ->  Sort  (cost=1190468.78..1191889.93 rows=568458 width=175) (actual time=95246.899..95246.905 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=601158 read=826986 dirtied=1322 written=86
         ->  HashAggregate  (cost=1169657.74..1175342.32 rows=568458 width=175) (actual time=94714.841..95075.593 rows=381577 loops=1)
               Buffers: shared hit=601155 read=826986 dirtied=1322 written=86
               ->  Hash Join  (cost=399505.14..1155446.29 rows=568458 width=175) (actual time=12155.515..89647.318 rows=1148270 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=601155 read=826986 dirtied=1322 written=86
                     ->  Hash Join  (cost=399503.58..1147628.43 rows=568458 width=153) (actual time=12155.459..88668.977 rows=1148270 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=601154 read=826986 dirtied=1322 written=86
                           ->  Merge Join  (cost=330475.58..1067231.27 rows=568458 width=12) (actual time=7514.499..81190.716 rows=1148270 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=567665 read=825197 dirtied=1322 written=86
                                 ->  Sort  (cost=330475.58..331909.33 rows=573501 width=8) (actual time=7514.354..7760.870 rows=574115 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51488kB
                                       Buffers: shared hit=216493 read=14600 dirtied=219
                                       ->  Bitmap Heap Scan on orders  (cost=12232.31..275621.82 rows=573501 width=8) (actual time=699.803..6144.383 rows=574115 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Buffers: shared hit=216493 read=14600 dirtied=219
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12088.93 rows=573501 width=0) (actual time=584.143..584.143 rows=576951 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared hit=2 read=1593
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..690812.26 rows=14957221 width=12) (actual time=0.112..69498.318 rows=14823276 loops=1)
                                       Buffers: shared hit=351172 read=810597 dirtied=1103 written=86
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=4639.011..4639.011 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=33489 read=1789
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.016..2200.501 rows=1500000 loops=1)
                                       Buffers: shared hit=33489 read=1789
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.029..0.029 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.010..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 95308.546 ms
(40 rows)

COMMIT;
COMMIT