2011/2/10 mac_man2008@yahoo.it <mac_man2008@yahoo.it>:
> Which operations invoke the sorting algorithms implemented in the sorting
> module (tuplesort.c) ?
> Of course, one of those operations invoking sorting is the ORDER BY clause
> and the DISTINCT too.
>
> Moreover, the Merge Join should be implemented invoking sorting.
>
> Is there any other operation invoking sorting?
AFAIK, all set operators except for UNION ALL. (I am probably missing
a whole boatload of other things.)
Nicolas