Re: machine-readable explain output

Robert Haas wrote:
> 3. We have existing precedent for this design pattern in, e.g. table_to_xml
>
> http://www.postgresql.org/docs/current/interactive/functions-xml.html
>
>   

Tables are flat, explain output is not.

If there is a relationship between the items then that needs to be 
expressed in the XML structure, either by use of child nodes or 
attributes. Relying on the sequence of nodes, if that's what you're 
doing, is not a good idea, and will make postprocessing the XML using 
XSLT, for example, quite a bit harder. (Processing a foo that comes 
after a bar is possible but not as natural as processing a foo that is a 
child or attribute of a bar)

Anyway, I think what this discussion points out is that we actually need 
a formal XML Schema for this output.

cheers

andrew