Re: patch: function xmltable

2017-01-31 14:57 GMT+01:00 Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>:

> Pavel Stehule wrote:
> > 2017-01-24 21:38 GMT+01:00 Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>:
>
> > > I think it would be good to have a more complex test case in regress --
> > > let's say there is a table with some simple XML values, then we use
> > > XMLFOREST (or maybe one of the table_to_xml functions) to generate a
> > > large document, and then XMLTABLE uses that document as input document.
> >
> > I have a 16K lines long real XML 6.MB. Probably we would not to append it
> > to regress tests.
> >
> > It is really fast - original customer implementation 20min, nested our
> > xpath implementation 10 sec, PLPython xml reader 5 sec, xmltable 400ms
>
> That's great numbers, kudos for the hard work here. That will make for
> a nice headline in pg10 PR materials. But what I was getting at is that
> I would like to exercise a bit more of the expression handling in
> xmltable execution, to make sure it doesn't handle just string literals.
>

I'll try to write some more dynamic examples.

>
> > I have a plan to create tests based on pg_proc and CTE - if all works,
> then
> > the query must be empty
> >
> > with x as (select proname, proowner, procost, pronargs,
> > array_to_string(proargnames,',') as proargnames,
> > array_to_string(proargtypes,',') as proargtypes from pg_proc), y as
> (select
> > xmlelement(name proc, xmlforest(proname, proowner, procost, pronargs,
> > proargnames, proargtypes)) as proc from x), z as (select xmltable.* from
> y,
> > lateral xmltable('/proc' passing proc columns proname name, proowner oid,
> > procost float, pronargs int, proargnames text, proargtypes text)) select
> *
> > from z except select * from x;
>
> Nice one :-)
>
> --
> Álvaro Herrera https://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>