Re: generic options for explain

On Monday 25 May 2009 18:02:53 Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > This is all much more complicated than what I proposed, and I fail to
> > see what it buys us.  I'd say that you're just reinforcing the point I
> > made upthread, which is that insisting that XML is the only way to get
> > more detailed information will just create a cottage industry of
> > beating that XML output format into submission.
>
> The impression I have is that (to misquote Churchill) XML is the worst
> option available, except for all the others.  We need something that can
> represent a fairly complex data structure, easily supports addition or
> removal of particular fields in the structure (including fields not
> foreseen in the original design), is not hard for programs to parse,
> and is widely supported --- ie, "not hard" includes "you don't have to
> write your own parser, in most languages".  How many realistic
> alternatives are there?

I think we are going in the wrong direction.  No one has said that they want a 
machine-readable EXPLAIN format.  OK, there are historically about three 
people that want one, but they have already solved the problem of parsing the 
current format.  And without having writtens such a parser myself I think that 
the current format is not inherently hard to parse.

What people really want is optional additional information in the human-
readable format.  Giving them a machine readable format does not solve the 
problem.  Giving them a machine readable format with all-or-none of the 
optional information and saying "figure it out yourself" does not solve 
anything either.  The same people who currently complain will continue to 
complain.