Re: machine-readable explain output v4

Tom Lane wrote:
> Mike <ipso@snappymail.ca> writes:
>   
>> Have any tool authors stepped up and committed resources to utilizing
>> this feature in the near term?
>>     
>
> I don't think anyone's promised much.  If you want to have a go at using
> it, we'd be very happy.
>
>   
>> I'm guessing that my vision likely exceeds the scope of this feature in
>> its initial form at least, but assuming no one else has stepped up, I'm
>> more than willing to start committing resources as early as this
>> weekend with the understanding that this feature is still in
>> development and likely will change several times before or if its
>> finally committed for 8.5. 
>>     
>
> It's definitely committed for 8.5, but the exact format of the output
> is (obviously) still subject to change.
>
>             
>   

Good. I had a look at this for a little while yesterday. I built it, did 
an install, loaded auto_explain and then ran the regression tests. I 
didn't like the output much. It looks like the XML has been dumbed down 
to fit a data model that works for JSON as well, particularly in the 
lack of use of attributes. An XML processor won't care that much, but 
humans will certainly find it more tiresome to read. In effect we are 
swapping horizontal expansion for vertical expansion. It would be nicer 
to be able to fit a plan into a screen.

I also took the last relaxng spec I could find and used a nice little 
tool called Trang to translate it into an XML Schema spec. The good news 
is that that worked. The bad news is that the spec almost certainly 
needs some tightening, especially around those elements that probably 
should be XML attributes.

cheers

andrew