Re: Sort performance cliff with small work_mem

On Wed, May 2, 2018 at 10:43 AM, Heikki Linnakangas <hlinnaka@iki.fi> wrote:
> Independently of this, perhaps we should put in special case in
> dumptuples(), so that it would never create a run with fewer than maxTapes
> tuples. The rationale is that you'll need to hold that many tuples in memory
> during the merge phase anyway, so it seems silly to bail out before that
> while building the initial runs. You're going to exceed work_mem by the
> roughly same amount anyway, just in a different phase. That's not the case
> in this example, but it might happen when sorting extremely wide tuples.

-1 from me. What about the case where only some tuples are massive?

-- 
Peter Geoghegan