Re: [HACKERS] Native XML

2011-03-10 Thread Robert Haas
On Wed, Mar 9, 2011 at 7:03 PM, Josh Berkus j...@agliodbs.com wrote: Then I think the answer is that we need both data types.  One for text-XML and one for binary-XML. That's what I think, too. I'm not sure whether we want both of them in core, but I think the binary-XML one would, at a

Re: [HACKERS] Native XML

2011-03-09 Thread Bruce Momjian
Robert Haas wrote: On Mon, Feb 28, 2011 at 10:30 AM, Tom Lane t...@sss.pgh.pa.us wrote: Well, in principle we could allow them to work on both, just the same way that (for instance) + is a standardized operator but works on more than one datatype. ?But I agree that the prospect of two

Re: [HACKERS] Native XML

2011-03-09 Thread Robert Haas
On Wed, Mar 9, 2011 at 1:11 PM, Bruce Momjian br...@momjian.us wrote: Robert Haas wrote: On Mon, Feb 28, 2011 at 10:30 AM, Tom Lane t...@sss.pgh.pa.us wrote: Well, in principle we could allow them to work on both, just the same way that (for instance) + is a standardized operator but works

Re: [HACKERS] Native XML

2011-03-09 Thread Yeb Havinga
On 2011-03-09 19:30, Robert Haas wrote: On Wed, Mar 9, 2011 at 1:11 PM, Bruce Momjianbr...@momjian.us wrote: Robert Haas wrote: On Mon, Feb 28, 2011 at 10:30 AM, Tom Lanet...@sss.pgh.pa.us wrote: Well, in principle we could allow them to work on both, just the same way that (for instance) +

Re: [HACKERS] Native XML

2011-03-09 Thread Anton
On 03/09/2011 08:21 PM, Yeb Havinga wrote: On 2011-03-09 19:30, Robert Haas wrote: On Wed, Mar 9, 2011 at 1:11 PM, Bruce Momjian br...@momjian.us wrote: Robert Haas wrote: On Mon, Feb 28, 2011 at 10:30 AM, Tom Lane t...@sss.pgh.pa.us wrote: Well, in principle we could

Re: [HACKERS] Native XML

2011-03-09 Thread Josh Berkus
On 3/9/11 10:11 AM, Bruce Momjian wrote: If you are storing xml in an xml column just to get it validated, and doing no processing in the DB, then you'd probably prefer our current representation. If you want to build functional indexes on xpath expressions, and then run queries that extract

Re: [HACKERS] Native XML

2011-03-02 Thread Nicolas Barbier
2011/3/1 Andrew Dunstan and...@dunslane.net: I think hierarchical data really only scratches the surface of the problem. It would be nice to be able to specify all sorts of context for searches:   * foo after bar   * foo near bar   * foo and bar in the same paragraph   * foo as a

Re: [HACKERS] Native XML

2011-03-01 Thread Robert Haas
On Mon, Feb 28, 2011 at 6:54 PM, Andrew Dunstan and...@dunslane.net wrote: There seems to be an almost universal assumption that storing XML in its native form (i.e. a text stream) is going to produce inefficient results. Maybe it will, but I think it needs to be fairly convincingly

Re: [HACKERS] Native XML

2011-03-01 Thread Andrew Dunstan
On 03/01/2011 08:16 AM, Robert Haas wrote: On Mon, Feb 28, 2011 at 6:54 PM, Andrew Dunstanand...@dunslane.net wrote: There seems to be an almost universal assumption that storing XML in its native form (i.e. a text stream) is going to produce inefficient results. Maybe it will, but I think

Re: [HACKERS] Native XML

2011-03-01 Thread Kevin Grittner
Andrew Dunstan and...@dunslane.net wrote: On 02/28/2011 05:28 PM, Kevin Grittner wrote: Antonantonin.hou...@gmail.com wrote: it was actually the focal point of my considerations: whether to store plain text or 'something else'. There seems to be an almost universal assumption that storing

Re: [HACKERS] Native XML

2011-03-01 Thread Tom Lane
Kevin Grittner kevin.gritt...@wicourts.gov writes: I apparently didn't express myself very well, since you seem to have *completely* missed my point. I know we can do tsearch2 searches against XML, or JSON, or YAML, or (insert next week's new favorite format here). What we can't currently do

Re: [HACKERS] Native XML

2011-03-01 Thread Andrew Dunstan
On 03/01/2011 02:15 PM, Kevin Grittner wrote: Given that there were similar issues for other hierarchical data types, perhaps we need something similar to tsvector, but for hierarchical data. The extra layer of abstraction might not cost much when used for XML compared to the possible

Re: [HACKERS] Native XML

2011-02-28 Thread Anton
On 02/27/2011 11:57 PM, Peter Eisentraut wrote: On sön, 2011-02-27 at 10:45 -0500, Tom Lane wrote: Hmm, so this doesn't rely on libxml2 at all? Given the amount of pain that library has caused us, getting out from under it seems like a mighty attractive idea. This doesn't replace

Re: [HACKERS] Native XML

2011-02-28 Thread Andrew Dunstan
On 02/28/2011 04:25 AM, Anton wrote: On 02/27/2011 11:57 PM, Peter Eisentraut wrote: On sön, 2011-02-27 at 10:45 -0500, Tom Lane wrote: Hmm, so this doesn't rely on libxml2 at all? Given the amount of pain that library has caused us, getting out from under it seems like a mighty attractive

Re: [HACKERS] Native XML

2011-02-28 Thread Tom Lane
Andrew Dunstan and...@dunslane.net writes: On 02/28/2011 04:25 AM, Anton wrote: A question is of course, if potential new implementation must necessarily replace the existing one, immediately or at all. What I published is implemented as a new data type and thus pg_type.h and pg_proc.h are

Re: [HACKERS] Native XML

2011-02-28 Thread Robert Haas
On Sun, Feb 27, 2011 at 10:20 PM, Andrew Dunstan and...@dunslane.net wrote: No, I think the xpath implementation is from libxml2. But in any case, I think the problem is in the whole design of the xpath_table function, and not in the library used for running the xpath queries. i.e it's our

Re: [HACKERS] Native XML

2011-02-28 Thread Andrew Dunstan
On 02/28/2011 10:30 AM, Tom Lane wrote: The single most pressing problem we've got with XML right now is the poor state of the XPath extensions in contrib/xml2. If we don't see a meaningful step forward in that area, a new implementation of the xml datatype isn't likely to win acceptance.

Re: [HACKERS] Native XML

2011-02-28 Thread Tom Lane
Andrew Dunstan and...@dunslane.net writes: xpath_table is severely broken by design IMNSHO. We need a new design, but I'm reluctant to work on that until someone does LATERAL, because a replacement would be much nicer to design with it than without it. Well, maybe I'm missing something, but

Re: [HACKERS] Native XML

2011-02-28 Thread Robert Haas
On Mon, Feb 28, 2011 at 10:30 AM, Tom Lane t...@sss.pgh.pa.us wrote: Well, in principle we could allow them to work on both, just the same way that (for instance) + is a standardized operator but works on more than one datatype.  But I agree that the prospect of two parallel types with

Re: [HACKERS] Native XML

2011-02-28 Thread Andrew Dunstan
On 02/28/2011 10:51 AM, Tom Lane wrote: Andrew Dunstanand...@dunslane.net writes: xpath_table is severely broken by design IMNSHO. We need a new design, but I'm reluctant to work on that until someone does LATERAL, because a replacement would be much nicer to design with it than without it.

Re: [HACKERS] Native XML

2011-02-28 Thread Anton
On 02/28/2011 05:23 PM, Robert Haas wrote: On Mon, Feb 28, 2011 at 10:30 AM, Tom Lane t...@sss.pgh.pa.us wrote: Well, in principle we could allow them to work on both, just the same way that (for instance) + is a standardized operator but works on more than one datatype. But I agree that

Re: [HACKERS] Native XML

2011-02-28 Thread Kevin Grittner
Anton antonin.hou...@gmail.com wrote: it was actually the focal point of my considerations: whether to store plain text or 'something else'. Given that there were similar issues for other hierarchical data types, perhaps we need something similar to tsvector, but for hierarchical data. The

Re: [HACKERS] Native XML

2011-02-28 Thread Andrew Dunstan
On 02/28/2011 05:28 PM, Kevin Grittner wrote: Antonantonin.hou...@gmail.com wrote: it was actually the focal point of my considerations: whether to store plain text or 'something else'. There seems to be an almost universal assumption that storing XML in its native form (i.e. a text

Re: [HACKERS] Native XML

2011-02-27 Thread Tom Lane
Anton antonin.hou...@gmail.com writes: I've been playing with 'native XML' for a while and now wondering if further development of such a feature makes sense for Postgres. ... Unlike 'libxml2', the parser uses palloc()/pfree(). The output format is independent from any 3rd party code. Hmm,

Re: [HACKERS] Native XML

2011-02-27 Thread Andrew Dunstan
On 02/27/2011 10:45 AM, Tom Lane wrote: Antonantonin.hou...@gmail.com writes: I've been playing with 'native XML' for a while and now wondering if further development of such a feature makes sense for Postgres. ... Unlike 'libxml2', the parser uses palloc()/pfree(). The output format is

Re: [HACKERS] Native XML

2011-02-27 Thread Tom Lane
Andrew Dunstan and...@dunslane.net writes: On 02/27/2011 10:45 AM, Tom Lane wrote: Hmm, so this doesn't rely on libxml2 at all? Given the amount of pain that library has caused us, getting out from under it seems like a mighty attractive idea. How big a chunk of code do you think it'd be by

Re: [HACKERS] Native XML

2011-02-27 Thread David E. Wheeler
On Feb 27, 2011, at 11:23 AM, Tom Lane wrote: Well, that's why I asked --- if it's going to be a huge chunk of code, then I agree this is the wrong path to pursue. However, I do feel that libxml pretty well sucks, so if we could replace it with a relatively small amount of code, that might

Re: [HACKERS] Native XML

2011-02-27 Thread Tom Lane
David E. Wheeler da...@kineticode.com writes: On Feb 27, 2011, at 11:23 AM, Tom Lane wrote: No, because the xpath stuff is fundamentally broken, and nobody seems to know how to make libxslt do what we actually need. See the open bugs on the TODO list. XPath is broken? I use it heavily in

Re: [HACKERS] Native XML

2011-02-27 Thread Mike Fowler
On 27/02/11 19:37, David E. Wheeler wrote: On Feb 27, 2011, at 11:23 AM, Tom Lane wrote: Well, that's why I asked --- if it's going to be a huge chunk of code, then I agree this is the wrong path to pursue. However, I do feel that libxml pretty well sucks, so if we could replace it with a

Re: [HACKERS] Native XML

2011-02-27 Thread David E. Wheeler
On Feb 27, 2011, at 11:43 AM, Tom Lane wrote: XPath is broken? I use it heavily in the Perl module Test::XPath and now, in PostgreSQL, with my explanation extension. Well, if you're only using cases that work, you don't need to worry. Okay then. David -- Sent via pgsql-hackers mailing

Re: [HACKERS] Native XML

2011-02-27 Thread Tom Lane
Mike Fowler m...@mlfowler.com writes: I don't believe that XPath is fundamentally broken, but I think Tom may have meant xslt. When reviewing a recent patch to xml2/xslt I found a few bugs in the way were using libxslt, as well as a bug in the library itself (see

Fwd: Re: [HACKERS] Native XML

2011-02-27 Thread Anton
Sorry for resending, I forgot to add 'pgsql-hackers' to CC. Original Message Subject:Re: [HACKERS] Native XML Date: Sun, 27 Feb 2011 23:18:03 +0100 From: Anton antonin.hou...@gmail.com To: Tom Lane t...@sss.pgh.pa.us On 02/27/2011 04:45 PM, Tom Lane wrote

Re: [HACKERS] Native XML

2011-02-27 Thread Peter Eisentraut
On sön, 2011-02-27 at 10:45 -0500, Tom Lane wrote: Hmm, so this doesn't rely on libxml2 at all? Given the amount of pain that library has caused us, getting out from under it seems like a mighty attractive idea. This doesn't replace the existing xml functionality, so it won't help getting rid

Re: [HACKERS] Native XML

2011-02-27 Thread Andrew Dunstan
On 02/27/2011 03:06 PM, Tom Lane wrote: Mike Fowlerm...@mlfowler.com writes: I don't believe that XPath is fundamentally broken, but I think Tom may have meant xslt. When reviewing a recent patch to xml2/xslt I found a few bugs in the way were using libxslt, as well as a bug in the library

Re: [HACKERS] Native XML

2011-02-27 Thread Tom Lane
Andrew Dunstan and...@dunslane.net writes: On 02/27/2011 03:06 PM, Tom Lane wrote: The case that I don't think we have any idea how to solve is http://archives.postgresql.org/pgsql-hackers/2010-02/msg02424.php I'd forgotten about this. But as ugly as it is, I don't think it's libxml2's

Re: [HACKERS] Native XML

2011-02-27 Thread Andrew Dunstan
On 02/27/2011 10:07 PM, Tom Lane wrote: Andrew Dunstanand...@dunslane.net writes: On 02/27/2011 03:06 PM, Tom Lane wrote: The case that I don't think we have any idea how to solve is http://archives.postgresql.org/pgsql-hackers/2010-02/msg02424.php I'd forgotten about this. But as ugly as

Re: [HACKERS] Native XML

2011-02-26 Thread Josh Berkus
On 2/26/11 3:40 PM, Anton wrote: I've been playing with 'native XML' for a while and now wondering if further development of such a feature makes sense for Postgres. (By not having brought this up earlier I'm taking the chance that the effort will be wasted, but that's not something you should