Re: REVIEW: EXPLAIN and nfiltered

On Sat, Jan 22, 2011 at 11:55:51AM -0500, Tom Lane wrote:
> Hitoshi Harada <umi(dot)tanuki(at)gmail(dot)com> writes:
> > 2011/1/21 Florian Pflug <fgp(at)phlo(dot)org>:
> >> "Rows Skipped: nnn", maybe?
>
> > +1. Very straightforward to me.
>
> I didn't really care for that one, because I think it *won't* be
> straightforward when there's more than one filter condition at a node.
> Imagine
>
> Bitmap Heap Scan ...
> Recheck Cond: blah blah
> Rows Skipped: 42
> Filter Cond: blah blah blah
> Rows Skipped: 77
>
> To me, "rows skipped" sounds like a statement about the overall behavior
> of the plan node, and thus the above looks contradictory. Another point
> is that even if you're okay with the above for textual output, we do not
> have a choice about choosing distinct field names for the two counts for
> XML/JSON output.
>
> Reflecting on that, I'm inclined to suggest
>
> Bitmap Heap Scan ...
> Recheck Cond: blah blah
> Rows Removed by Recheck: 42
> Filter Cond: blah blah blah
> Rows Removed by Filter: 77
>
> or even more verbosely
>
> Bitmap Heap Scan ...
> Recheck Cond: blah blah
> Rows Removed by Recheck Cond: 42
> Filter Cond: blah blah blah
> Rows Removed by Filter Cond: 77
>
> ie repeat the label of the filtering condition exactly. This is looking
> pretty long, but from the viewpoint of vertical or horizontal space
> occupied by the printout, I doubt it matters.

+1 for this. It says what happened. :)

Cheers,
David.
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