Re: EXPLAIN: showing ReadStream / prefetch stats

On Tue, Apr 7, 2026 at 1:34 PM Tomas Vondra <tomas(at)vondra(dot)me> wrote:
>
> On 4/7/26 18:07, Melanie Plageman wrote:
>
> > I see I had bitmapheapscan use
> > if (!node->ss.ps.instrument || pcxt->nworkers == 0)
> > return;
> >
> > while seq scan uses
> > if (!estate->es_instrument || pcxt->nworkers == 0)
> > return;
> >
> > That does seem worth being consistent about. Though the estate one is
> > probably better to use and changing bitmapheapscan in this commit
> > might be noisy... I don't feel strongly either way.
>
> I'm not sure this is just a question of consistency, because BHS may
> need the shared instrumentation even if (es_instrument = 0), no? While
> the seqscan/tidrange scan only need it with EXPLAIN(IO).
>
> So I think the two nodes should check
>
> ((estate->es_instrument & INSTRUMENT_IO) == 0)

Makes sense to me.

I skimmed v14 quite quickly and LGTM.

- Melanie