Re: Memory prefetching while sequentially fetching from SortTuple array, tuplestore

On Wed, Sep 2, 2015 at 7:12 AM, Andres Freund <andres@anarazel.de> wrote:
> What worries me about adding explicit prefetching is that it's *highly*
> platform and even micro-architecture dependent. Why is looking three
> elements ahead the right value?

Because that was the fastest value following testing on my laptop. You
are absolutely right to point out that this isn't a good reason to go
with the patch -- I share your concern. All I can say in defense of
that is that other major system software does the same, without any
regard for the underlying microarchitecture AFAICT. So, yes,
certainly, more testing is required across a reasonable cross-section
of platforms to justify the patch.