Re: [BUGS] BUG #8516: Calling VOLATILE from STABLE function

2013-10-11 Thread Dimitri Fontaine
'Bruce Momjian'  writes:
> Well, we can't walk the function tree to know all called functions, and
> those they call, so we don't even try.

Inter function dependencies is a hard topic indeed. I still would like
to see some kind of progress being made someday. The general case is
turing complete tho, because you can use EXECUTE against programatically
generated SQL.

You could even generate a CREATE FUNCTION command from within a PL
function and EXECUTE it then call the created function… and I think I've
seen people do that in the past.

Still some kind of limited in scope static analysis for the cases where
it's possible to do so would be great. With pg_depend tracking so that
you know you're doing something wrong at DROP FUNCTION time.

Regards,
-- 
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support


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Re: [BUGS] BUG #8516: Calling VOLATILE from STABLE function

2013-10-11 Thread Terje Elde
On Oct 11, 2013, at 9:21 AM, Dimitri Fontaine  wrote:

> Inter function dependencies is a hard topic indeed. I still would like
> to see some kind of progress being made someday. The general case is
> turing complete tho, because you can use EXECUTE against programatically
> generated SQL.
> 
> You could even generate a CREATE FUNCTION command from within a PL
> function and EXECUTE it then call the created function… and I think I've
> seen people do that in the past.
> 
> Still some kind of limited in scope static analysis for the cases where
> it's possible to do so would be great. With pg_depend tracking so that
> you know you're doing something wrong at DROP FUNCTION time.

I'm not very familiar with PostgreSQL internals, so I might be way off here, 
and I'm asking as much out of curiousity as anything else…

Would it be possible (and make sense) to solve this in a completely different 
way, not walking the function tree or doing static analysis, but simply setting 
and checking a bit during execution?

That is, when you execute a STABLE function, set a bit (clear it when function 
is done), and always check it when executing any VOLATILE function?

If a volatile function checks the bit, and you're "inside" a stable function, 
you could then raise an exception for calling volatile inside stable?

Terje



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Re: [BUGS] Bit String expand bug

2013-10-11 Thread Tom Lane
Gabriel Ciubotaru  writes:
>  There's a problem with expanding Bit String data types, it make 
> right padding with 0 instead of left padding , making  the bit mask 
> almost useless.

You need to show an example of the problem; this report has no details
that would let us fix anything.

regards, tom lane


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Re: [BUGS] BUG #8516: Calling VOLATILE from STABLE function

2013-10-11 Thread Tom Lane
Terje Elde  writes:
> Would it be possible (and make sense) to solve this in a completely different 
> way, not walking the function tree or doing static analysis, but simply 
> setting and checking a bit during execution?

While it's possible that we could do something like that, I think it's
fairly unlikely that we would.  The reason is that it would disable
constructs that some people find useful; that is, sometimes it's
intentional that a stable function calls a volatile one.

A couple of examples:

1. You might want to make some database updates but continue to do queries
with a pre-update snapshot.  A single function can't accomplish that,
but the combination of a stable outer function with a volatile update
function can.

2. A security checking function (for use with Veil or the proposed row
security feature) might wish to log accesses without denying them.  To
do that it'd have to be volatile, so if we had a restriction like this
the function would fail when invoked within a stable function.

You can imagine various ways around such issues, but it would add a lot
of complication.

regards, tom lane


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[BUGS] BUG #8518: FreeBSD usage in 9.3.1

2013-10-11 Thread david . kumar
The following bug has been logged on the website:

Bug reference:  8518
Logged by:  david
Email address:  david.ku...@vsoftcorp.com
PostgreSQL version: 9.3.1
Operating system:   Windows 7
Description:

Hi All,


I had tried using FreeBSD disk encryption but unable to find tool to
encryption in Windows OS . can some one please help me in encrypting the
disk.


Thanks
David jaya Kumar. K



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Re: [BUGS] BUG #8516: Calling VOLATILE from STABLE function

2013-10-11 Thread Dwayne Towell
> According to the documentation, f() should be marked VOLATILE also, since
> calling f() produces side effects. PostgreSQL does not give a warning (or
> better yet, an error); I think it should.

I think the answer is that function authors are required to prevent
functions they mark as STABLE from calling VOLATILE functions.

--

I understand it's an error (at least usually), my question/issue is why does
PostgreSQL NOT give at least a warning when a programmer (probably
accidentally) calls a VOLATILE function in one that he has specifically
tagged as STABLE? The compiler has all the information to notify the
programmer of a mistake, but isn't. This violates a fundamental principle of
software engineering--take every opportunity to prevent errors.

Dwayne 



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[BUGS] Feature request - Information Schema enhancement

2013-10-11 Thread Joe Love
I know the Information Schema is a SQL standard, but it's somewhat lacking.
I was trying to write a web page  that showed a db table,it's  columns and
foreign keys.
All went well and I was able to get this tool working great using the
information_schema, problem is that some of the information_schema views
only show items that you own (not that you have access to) and as a result,
when I logged in as a DB user that didn't own some of the tables, the
constraints wouldn't show up. I was able to work around this by creating my
own information_schema view "all_constraint_column_usage" (using oracle's
naming convention as inspiration) that met my need. The view did exactly
what constraint_column_usage does, but I left off part one of the where
predicates that enabled this restriction.

Is this something that we'd ever consider implementing in
information_schema, or is there a better place to do something like this?
Using the PG tables may change from version to version so that's out, but
it'd be nice to have views like the ones in information_schema that weren't
OID based.