Re: machine-readable explain output

Robert Haas <robertmhaas@gmail.com> writes:
> On Sat, Jun 13, 2009 at 6:40 PM, Tom Lane<tgl@sss.pgh.pa.us> wrote:
>> I believe we have things set up so that you can still print "xml" data
>> without libxml configured in. �We'd need to be sure casting to text
>> works too, but other than that I don't see an issue here.

> Hmm, I just tried to do this by modifying ExplainResultDesc to use
> XMLOID rather than TEXTOID when stmt->format == EXPLAIN_FORMAT_XML,
> and sure enough, explain (format xml) ... fails when --with-libxml is
> not specified.

That's because the code goes through BuildTupleFromCStrings, which
invokes xml_in in this scenario, and xml_in (as opposed to xml_out)
does depend on libxml.

However, using BuildTupleFromCStrings is wasteful/stupid for *both*
text and xml output, so it seems like getting rid of it is the thing
to do here.
        regards, tom lane