cannot disable hashSetOp

hello

I looked on issue with consuming memory by query

HashSetOp Except (cost=0.00..297100.69 rows=594044 width=30)
-> Append (cost=0.00..234950.32 rows=8286716 width=30)
-> Subquery Scan on "*SELECT* 1" (cost=0.00..168074.62
rows=5940431 width=29)
-> Seq Scan on ac (cost=0.00..108670.31 rows=5940431 width=29)
-> Subquery Scan on "*SELECT* 2" (cost=0.00..66875.70
rows=2346285 width=32)
-> Seq Scan on artist_credit (cost=0.00..43412.85
rows=2346285 width=32)

I was surprised, because I didn't find any way how to disable hashing.

Is there some way?

Pavel