guyren(at)icloud(dot)com writes:
> The Halloween problem is that it is a challenge for the database if you’re updating a field that is also in the WHERE clause of the same query.
> I just saw a presentation from someone about how in SQL Server he recommended writing changes to a temp table and then writing them to the table as being much more efficient.
That's nonsense as far as Postgres is concerned.
regards, tom lane