QUERY PLAN                                 
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 Merge Join  (cost=xxx rows=1 width=29)
   Merge Cond: (t1.c1 = t2.c1)
   ->  Index Scan using t1_i1 on t1  (cost=xxx rows=1000 width=15)
   ->  Sort  (cost=xxx rows=100 width=14)
         Sort Key: t2.c1
         ->  Seq Scan on t2  (cost=xxx rows=100 width=14)
(6 rows)