Re: Scrollable cursors and Sort performance

Simon Riggs <simon@2ndquadrant.com> writes:
> Which shows that the *unnecessary* final merge takes 344 secs, adding
> approximately 60% to the elapsed time of the query and nearly doubling
> the CPU requirement.

The merge step would certainly have to happen anyway, so this claim is
not justified.  You have not presented any evidence about how much of
the reported time is actually I/O related.
        regards, tom lane