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=1195372.46..1195372.51 rows=20 width=175) (actual time=32889.624..32889.631 rows=20 loops=1)
   Buffers: shared hit=669869 read=758161 dirtied=1544 written=3154
   ->  Sort  (cost=1195372.46..1196803.66 rows=572479 width=175) (actual time=32889.619..32889.623 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=669869 read=758161 dirtied=1544 written=3154
         ->  HashAggregate  (cost=1174414.21..1180139.00 rows=572479 width=175) (actual time=32374.806..32704.759 rows=381586 loops=1)
               Buffers: shared hit=669866 read=758161 dirtied=1544 written=3154
               ->  Hash Join  (cost=401766.83..1160102.24 rows=572479 width=175) (actual time=4645.025..28519.561 rows=1148224 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=669866 read=758161 dirtied=1544 written=3154
                     ->  Hash Join  (cost=401765.27..1152229.09 rows=572479 width=153) (actual time=4644.985..27929.533 rows=1148224 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=669865 read=758161 dirtied=1544 written=3154
                           ->  Merge Join  (cost=332737.27..1071751.51 rows=572479 width=12) (actual time=2318.906..23200.276 rows=1148224 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=634596 read=758152 dirtied=1544 written=3154
                                 ->  Sort  (cost=332737.24..334184.77 rows=579015 width=8) (actual time=2318.743..2480.106 rows=574181 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51491kB
                                       Buffers: shared hit=230497 read=1809 dirtied=362
                                       ->  Bitmap Heap Scan on orders  (cost=12576.89..277316.12 rows=579015 width=8) (actual time=367.369..2080.086 rows=574181 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Buffers: shared hit=230497 read=1809 dirtied=362
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12432.14 rows=579015 width=0) (actual time=272.382..272.382 rows=579875 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared hit=79 read=1580
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..692911.58 rows=14993753 width=12) (actual time=0.123..17910.469 rows=14822651 loops=1)
                                       Buffers: shared hit=404099 read=756343 dirtied=1182 written=3154
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2324.106..2324.106 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35269 read=9
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.013..757.784 rows=1500000 loops=1)
                                       Buffers: shared hit=35269 read=9
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.021..0.021 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=0.008..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 32954.736 ms
(40 rows)

COMMIT;
COMMIT