Re: machine-readable explain output

On Tuesday 16 June 2009 16:22:27 Robert Haas wrote:
> 1. It didn't seem very wise to go with the approach of trying to do
> EVERYTHING with attributes. If I did that, then I'd either get really
> long lines that were not easily readable, or I'd have to write some
> kind of complicated line wrapping code (which didn't seem to make a
> lot of sense for a machine-readable format). The current format isn't
> the most beautiful thing I've ever seen, but you don't need a parser
> to make sense of it, just a bit of patience.

There are obviously a lot of ways to go about defining an XML format, but here
is another one of them:

A plan is a tree of plan nodes. Each node has some information attached to
it, such as row counts and costs.

If you consider an XML document to be a tree of element nodes, then this falls
into place naturally. Each plan is an element, and all the other information
are attributes.

With this, visual explain would be completely trivial.