Re: EXPLAIN omits schema?

Gregory Stark wrote:
> "Joshua D. Drake" <jd@commandprompt.com> writes:
> 
>>> I agree. XML seems like a fairly natural fit for this. Just as people should
>>> not try to shoehorn everything into XML, neither should they try to shoehorn
>>> everything into a relational format either.
>>>
>>> Now all we need is an XML schema for it ;-)
>> Well I am not a big fan of XML but it certainly seems applicable in this
>> case.
> 
> I'm not a fan either so perhaps I'm biased, but this seems like a good example
> of where it would be an *awful* idea.
> 
> Once you have an XML plan what can you do with it? All you can do is parse it
> into constituent bits and display it. You cant do any sort of comparison
> between plans, aggregate results, search for plans matching constraints, etc.

Honestly, I had never even considered doing such a thing. I would just 
like a nice way to parse explain output :)

Joshua D. Drake


> 
> How would I, with XML output, do something like:
> 
> SELECT distinct node.relation 
>   FROM plan_table 
>  WHERE node.expected_rows < node.actual_rows*2;
> 
> or
> 
> SELECT node.type, average(node.ms/node.cost)
>   FROM plan_table 
>  GROUP BY node.type;
> 


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