Re: patch: function xmltable

Alvaro Herrera <alvherre@2ndquadrant.com>

From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Craig Ringer <craig@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2016-11-24T17:29:46Z
Lists: pgsql-hackers
Pavel Stehule wrote:
> Hi
> 
> 2016-11-24 0:13 GMT+01:00 Alvaro Herrera <alvherre@2ndquadrant.com>:
> 
> > Oh my, I just noticed we have a new xpath preprocessor in this patch
> > too.  Where did this code come from -- did you write it all from
> > scratch?
> 
> I wrote it from scratch - libxml2 has not any API for iteration over XPath
> expression (different than iteration over XPath expression result), and
> what I have info, there will not be any new API in libxml2.

Okay, I agree that the default namespace stuff looks worthwhile in the
long run.  But I don't have enough time to review the xpath parser stuff
in the current commitfest, and I think it needs at the very least a lot
of additional code commentary.

However I think the rest of it can reasonably go in -- I mean the SQL
parse of it, analysis, executor.  Let me propose this: you split the
patch, leaving the xpath_parser.c stuff out and XMLNAMESPACES DEFAULT,
and we introduce just the TableExpr stuff plus the XMLTABLE function.  I
can commit that part in the current commitfest, and we leave the
xpath_parser plus associated features for the upcoming commitfest.

Deal?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


Commits

  1. Support XMLTABLE query expression

  2. Create <sect3> in the functions-xml section

  3. Improve handling of "UPDATE ... SET (column_list) = row_constructor".

  4. Add xmlexists function