Re: EXPLAIN and nfiltered

On Thursday 18 November 2010 17:48:43 Marko Tiikkaja wrote:
> On 2010-11-18 6:44 PM +0200, Andres Freund wrote:
> > On Thursday 18 November 2010 16:45:23 Marko Tiikkaja wrote:
> >> Here's a patch for showing in EXPLAIN ANALYZE the number of rows a plan
> >
> >> qual filtered from a node's input. The output looks like this:
> > If it supports the same for index-scans I *really* like it and even
> > proposed a patch earlier (4A16A8AF(dot)2080508(at)anarazel(dot)de)
> > I still find myself constantly wishing to have something like that...
> > Especially when wondering if it might be worthwile to add another column
> > (which is implemented as an additional qual atm) should get included in a
> > multiicolumn index.
> >
> > It was shot down at the time because it might break some explain-parsers
> > expectations. Imho that argument is less valid these days.
>
> I have to admit, I didn't query the archives before looking at this. I
> guess I should have. This patch supports all Scan nodes, and I think
> that's the right thing to do.
Uh. No worries. That was my first pg-patch, I doubt it was well-done ;-)

> I agree 100% that breaking the parseability (is that a word?) of the
> EXPLAIN output is not really an argument these days, so we might want to
> give this some thought.
Yes.

Andres