Re: machine-readable explain output v4

On Wed, 2009-08-12 at 16:51 +0200, Csaba Nagy wrote:
> I argue that a sufficiently complicated explain output will never be
> easily navigated in a text browser, however much you would like it. If
> you do a where clause with 100 nested ANDs (which occasionally happens
> here), I don't think you'll be able to cleanly show that in a text
> browser - it will simply not fit in no matter how you format it. But
> using the right GUI tool (even a generic XML one) it would be easy to
> just temporarily collapse the whole top AND and have a clean view of the
> rest.

Just a small note: I don't know how the machine-readable auto-explain
output actually looks like, so I just assumed individual conditions will
have their own XML node. But even if they don't have and the AND thing
would be flat in the explain output, the same argument applies to even a
few 10s of joins or sub-selects (and we do have that too). Sometimes
collapsing parts of the plan would help big time in having a clean
picture, which (starting with a certain complexity of the query) you
will have a hard time to do in plain text regardless of the formatting.
I do have plenty of explain outputs (from 8.2 postgres) which don't fit
on my screen in text form even without further details I gather you can
get in the machine readable form.

Cheers,
Csaba.