Re: remove contrib/xml2

I did some tests followed Robert's test cases on both postgresql 8.4.2-0ubu
and 8.3.8-1, OS: Ubuntu Karmic.

1) 1st test case, it doesn't crash on 8.3.8 but crash on 8.4.2;
2) 2nd test case, both 8.3.8 and 8.4.2 are fine, and no warning (different
from Robert's test?);
3) 3rd test case (and modified test case for 8.3.8), both 8.3.8 and 8.4.2
are not correct, same with Robert's test (8.5 beta?);

*************************************
1st test case:
==================
8.3.8
==================
conifer=# CREATE TABLE xpath_test (id integer NOT NULL, t xml);
CREATE TABLE
conifer=# INSERT INTO xpath_test VALUES (1, '<doc><int>1</int></doc>');
INSERT 0 1
conifer=# SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int',
'true') as t(id int4);
id
----
1
(1 row)

==================
8.4.2
==================
conifer=# CREATE TABLE xpath_test (id integer NOT NULL, t xml);
CREATE TABLE
conifer=# INSERT INTO xpath_test VALUES (1, '<doc><int>1</int></doc>');
INSERT 0 1
conifer=# SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int',
'true') as t(id int4);
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!>
*************************************

*************************************
2nd test case
==================
8.3.8 and 8.4.2
==================
conifer=# CREATE TABLE xpath_test (id integer NOT NULL, t text);
CREATE TABLE
conifer=# INSERT INTO xpath_test VALUES (1, '<doc><int>1</int></doc>');
INSERT 0 1
conifer=# SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int',
'true') as t(id int4);
id
----
1
(1 row)
*************************************

*************************************
3rd test case
==================
8.3.8 and 8.4.2
==================
conifer=# CREATE TABLE xpath_test (id integer NOT NULL, t text);
CREATE TABLE
conifer=# INSERT INTO xpath_test VALUES (1, '<rowlist><row a="1"/><row a="2"
b="oops"/></rowlist>');
INSERT 0 1
conifer=# SELECT * FROM xpath_table('id', 't', 'xpath_test',
'/rowlist/row/@a|/rowlist/row/@b', 'true') as t(id int4, a text, b text);
id | a | b
----+---+------
1 | 1 | oops
1 | 2 |
(2 rows)

==================
8.3.8 (modified 3rd test case, because 8.3.8 won't crash using xml)
==================
conifer=# CREATE TABLE xpath_test (id integer NOT NULL, t xml);
CREATE TABLE
conifer=# INSERT INTO xpath_test VALUES (1, '<rowlist><row a="1"/><row a="2"
b="oops"/></rowlist>');
INSERT 0 1
conifer=# SELECT * FROM xpath_table('id', 't', 'xpath_test',
'/rowlist/row/@a|/rowlist/row/@b', 'true') as t(id int4, a text, b text);
id | a | b
----+---+------
1 | 1 | oops
1 | 2 |
(2 rows)
*************************************

For 1st test case, not sure if some paths applied to 8.3 haven't been
applied to 8.4, or other reasons cause the difference between 8.3.8 and
8.4.2.

Any ideas or comments?

Thank you,
M Z

On Mon, Feb 1, 2010 at 8:44 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> On Mon, Feb 1, 2010 at 5:23 PM, Andrew Dunstan <andrew(at)dunslane(dot)net>
> wrote:
> > Robert Haas wrote:
> >> (2) add a very, very large warning that this will crash if you do
> >> almost anything with it.
> >
> > I think that's an exaggeration. Certain people are known to be using it
> > quite successfully.
>
> Hmm. Well, all I know is that the first thing I tried crashed the server.
>
> CREATE TABLE xpath_test (id integer NOT NULL, t xml);
> INSERT INTO xpath_test VALUES (1, '<doc><int>1</int></doc>');
> SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int', 'true')
> as t(id int4);
>
> It doesn't crash if you change the type of t from xml to text; instead
> you get a warning about some sort of memory allocation problem.
>
> DROP TABLE xpath_test;
> CREATE TABLE xpath_test (id integer NOT NULL, t text);
> INSERT INTO xpath_test VALUES (1, '<doc><int>1</int></doc>');
> SELECT * FROM xpath_table('id', 't', 'xpath_test', '/doc/int', 'true')
> as t(id int4);
>
> yields:
>
> WARNING: problem in alloc set ExprContext: bogus aset link in block
> 0x14645e0, chunk 0x14648b8
>
> And then there's this (see also bug #5285):
>
> DELETE FROM xpath_test;
> INSERT INTO xpath_test VALUES (1, '<rowlist><row a="1"/><row a="2"
> b="oops"/></rowlist>');
> SELECT * FROM xpath_table('id', 't', 'xpath_test',
> '/rowlist/row/@a|/rowlist/row/@b', 'true') as t(id int4, a text, b
> text);
>
> which yields an answer that is, at least, extremely surprising, if not
> flat-out wrong:
>
> id | a | b
> ----+---+------
> 1 | 1 | oops
> 1 | 2 |
> (2 rows)
>
> Bugs #4953 and #5079 can also be reproduced in CVS HEAD. Both crash the
> server.
>
> ...Robert
>
> --
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