Re: Lowering the ever-growing heap->pd_lower

On Thu, Apr 7, 2022 at 7:01 PM Andres Freund <andres@anarazel.de> wrote:
> On 2022-04-04 19:24:22 -0700, Peter Geoghegan wrote:
> > We should definitely increase MaxHeapTuplesPerPage before too long,
> > for a variety of reasons that I have talked about in the past. Its
> > current value is 291 on all mainstream platforms, a value that's
> > derived from accidental historic details -- which predate HOT.
>
> I'm on-board with that - but I think we should rewrite a bunch of places that
> use MaxHeapTuplesPerPage sized-arrays on the stack first. It's not great using
> several KB of stack at the current the current value already (*), but if it grows
> further...

I agree that the value of 291 is pretty much accidental, but it also
seems fairly generous to me. The bigger you make it, the more space
you can waste. I must have missed (or failed to understand) previous
discussions about why raising it would be a good idea.

-- 
Robert Haas
EDB: http://www.enterprisedb.com