Re: machine-readable explain output

On 06/17/2009 04:27 PM, Peter Eisentraut wrote:
> 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.
So, the only change from the current schema would be to do move all 
additional information into attributes?

> With this, visual explain would be completely trivial.
Only that some attributes may need some more structure than a single 
scalar value.

Also that would need extra handling for each attribute to consider if 
its a information about planning or execution...


Andres