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 '1993-10-01'
	and o_orderdate < cast(date '1993-10-01' + 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=1187526.65..1187526.70 rows=20 width=176) (actual time=32182.339..32182.347 rows=20 loops=1)
   Buffers: shared hit=699242 read=714624 written=32142
   ->  Sort  (cost=1187526.65..1188959.43 rows=573112 width=176) (actual time=32182.335..32182.341 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=699242 read=714624 written=32142
         ->  HashAggregate  (cost=1166545.23..1172276.35 rows=573112 width=176) (actual time=31676.100..32033.829 rows=381124 loops=1)
               Buffers: shared hit=699239 read=714624 written=32142
               ->  Hash Join  (cost=399105.26..1152217.43 rows=573112 width=176) (actual time=4480.419..27682.445 rows=1147141 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=699239 read=714624 written=32142
                     ->  Hash Join  (cost=399103.69..1144335.57 rows=573112 width=154) (actual time=4480.367..27088.975 rows=1147141 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=699238 read=714624 written=32142
                           ->  Merge Join  (cost=330075.69..1063845.33 rows=573112 width=12) (actual time=1999.945..22088.237 rows=1147141 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=699236 read=679348 written=32142
                                 ->  Sort  (cost=330075.67..331521.76 rows=578434 width=8) (actual time=1999.853..2169.943 rows=573178 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51444kB
                                       Buffers: shared hit=228313 read=1730
                                       ->  Bitmap Heap Scan on orders  (cost=12262.84..274714.35 rows=578434 width=8) (actual time=460.256..1797.812 rows=573178 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-10-01'::date) AND (o_orderdate < '1994-01-01'::date))
                                             Buffers: shared hit=228313 read=1730
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12118.24 rows=578434 width=0) (actual time=337.915..337.915 rows=574279 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-10-01'::date) AND (o_orderdate < '1994-01-01'::date))
                                                   Buffers: shared read=1570
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..687917.19 rows=14891675 width=12) (actual time=0.070..17221.694 rows=14808183 loops=1)
                                       Buffers: shared hit=470923 read=677618 written=32142
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=2477.480..2477.480 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=2 read=35276
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.018..1077.490 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276
                     ->  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=0.008..0.012 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 32252.608 ms
(40 rows)

COMMIT;
COMMIT