Frits Jalvingh <jal(at)etc(dot)to> writes:
> The "good" news is that this effect is apparently caused by something else.
> I fired those statements through an IDE (IntelliJ) written in Java and
> using jdbc. There seems to be something odd going on in there, because when
> I paste the query in psql then the effect with and without explain looks
> the same: 3 processes of which 2 "parallel workers" doing enormous amounts
> of I/O at 50..90% CPU. I will try to find out what easter egg in either
> that IDE or the JDBC driver causes this 8-/.
Ah. Something about query parameterization, is my bet.
regards, tom lane