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Postgres Process in Kernel Mode?

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From:	"moises" <moises(at)cedaivc(dot)co(dot)cu>
To:	<pgsql-hackers(at)postgresql(dot)org>
Subject:	Postgres Process in Kernel Mode?
Date:	2006-07-31 14:55:59
Message-ID:	20060731205541.854399FB30A@postgresql.org
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Lists:	pgsql-hackers

Hello,

I'm new in postgres SQL and I have some questions about the space where
postgres process run.

1-Can any body say me what libs use postgres for make system calls, for
example LIBC?

2-Can any body talk me if some postgres process can run in Linux kernel
space?

3- Some body knows if exist some projects that ports postgres process on
Linux kernel space.

I was read some source code of postgres, like,

Postgres.C and others.

I was found C instructions like Printf, that's prohibitive for Linux kernel
applications, for example in kernel mode we use printk.

I suppose that postgres are ported in a user space only. I'm Ok?

Thanks

Moises

From:	Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To:	moises <moises(at)cedaivc(dot)co(dot)cu>
Cc:	pgsql-hackers(at)postgresql(dot)org
Subject:	Re: Postgres Process in Kernel Mode?
Date:	2006-07-31 21:06:20
Message-ID:	20060731210620.GL20962@alvh.no-ip.org
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Lists:	pgsql-hackers

moises wrote:

> 1-Can any body say me what libs use postgres for make system calls, for
> example LIBC?

libc and a lot others.

> 2-Can any body talk me if some postgres process can run in Linux kernel
> space?

No.

> 3- Some body knows if exist some projects that ports postgres process on
> Linux kernel space.

No that we've heard lately. (But I remember a guy with a .cu domain
asking not long ago, maybe it was you.)

> I was found C instructions like Printf, that's prohibitive for Linux kernel
> applications, for example in kernel mode we use printk.

That's because Postgres is a user-space program and there are no
intentions to change that.

> I suppose that postgres are ported in a user space only. I'm Ok?

Yes.

If you prefer spanish, I suggest you subscribe to the pgsql-es-ayuda
list. There is at least one Postgres hacker there.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.

From:	Chris Browne <cbbrowne(at)acm(dot)org>
To:	pgsql-hackers(at)postgresql(dot)org
Subject:	Re: Postgres Process in Kernel Mode?
Date:	2006-07-31 21:21:28
Message-ID:	60slkhjwrr.fsf@dba2.int.libertyrms.com
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moises(at)cedaivc(dot)co(dot)cu ("moises") writes:

> <html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns="http://www.w3.org/TR/REC-html40">
>
> <head>
> <meta http-equiv=Content-Type content="text/html; charset=us-ascii">
> <meta name=Generator content="Microsoft Word 11 (filtered medium)">
> <style>
> 
> </style>
>
> </head>
>
> <body lang=ES link=blue vlink=purple>
>
> <div class=Section1>
>
> 10.0pt;font-family:Arial'>Hello,<o:p></o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'>I’m new in postgres SQL and I have some
> questions about the space where postgres process run.<o:p></o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'>1-Can any body say me what libs use postgres for make
> system calls, for example LIBC? <o:p></o:p>

You can easily determine this yourself using ldd. The answer will
vary depending on what options you use when compiling it.

> 10.0pt;font-family:Arial'>2-Can any body talk me if some postgres process can
> run in Linux kernel space? <o:p></o:p>

Yes, it doesn't.

> 10.0pt;font-family:Arial'>3- Some body knows if exist some projects that ports postgres
> process on Linux kernel space.<o:p></o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'>I was read some source code of postgres, like, <o:p></o:p>
>
> 10.0pt;font-family:Arial'>Postgres.C and others…<o:p></o:p>
>
> 10.0pt;font-family:Arial'> <o:p></o:p>
>
> 10.0pt;font-family:Arial'>I was found C instructions like Printf, that’s prohibitive
> for Linux kernel applications, for example in kernel mode we use printk.<o:p></o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'>I suppose that postgres are ported in a user space
> only. I’m Ok?<o:p></o:p>

That's correct.

> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'>Thanks <o:p></o:p>
>
> 10.0pt;font-family:Arial'>Moises<o:p></o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'><o:p> </o:p>
>
> 10.0pt;font-family:Arial'>- <o:p></o:p>
>
> </div>
>
> </body>
>
> </html>

You might want to consider using an email client that doesn't slobber:
<o:p> </o:p>
around everywhere.

It's really irritating to have to read around that "deteriorata."
--
(format nil "~S(at)~S" "cbbrowne" "ntlug.org")
http://www3.sympatico.ca/cbbrowne/advocacy.html
A cool feature of OOP is that the simplest examples are 500 lines.
-- Peter Sestoft

From:	Chris Browne <cbbrowne(at)acm(dot)org>
To:	pgsql-hackers(at)postgresql(dot)org
Subject:	OSCON fallout - Compressed Annealing optimizer
Date:	2006-07-31 22:25:30
Message-ID:	60k65tjtt1.fsf_-_@dba2.int.libertyrms.com
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Lists:	pgsql-hackers

Robert Hansen did a talk at OSCON on a compressed annealing framework
called Djinni: <http://sixdemonbag.org/Djinni/>

It's a framework to use compressed annealing (a derivative of
simulated annealing) for finding approximate solutions to NP-complete
problems such as the TSP with time windows. Note that while Djinni is
implemented in C++, it already supports embedding via SWIG, and has a
C wrapper and is accessible from other languages. And it's
BSD-licensed...

This has the potential to be an alternative to the present use of GEQO
for query optimization for cases of large joins (e.g. - involving
large numbers of tables).

On the one hand, I'm somewhat suited to looking at this in that I have
the operations research background to know what they're talking about.
On the other hand, I'm not familiar with the optimizer, nor do I deal
with sorts of cases with so many joins that this would be worthwhile.

I've bounced a ToDo entry over to Bruce, and am making sure this is
documented here on pgsql.hackers so that a web search can readily find
it in the future...
--
"cbbrowne","@","cbbrowne.com"
http://www3.sympatico.ca/cbbrowne/
"It is far from complete, but it should explain enough that you don't
just stare at your sendmail.cf file like a deer staring at an oncoming
truck." -- David Charlap

From:	Lexington Luthor <Lexington(dot)Luthor(at)gmail(dot)com>
To:	pgsql-hackers(at)postgresql(dot)org
Subject:	Re: Postgres Process in Kernel Mode?
Date:	2006-08-01 08:18:11
Message-ID:	ean2o7$q05$1@sea.gmane.org
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Lists:	pgsql-hackers

moises wrote:
> Hello,
>
> I’m new in postgres SQL and I have some questions about the space where
> postgres process run.
>
> 1-Can any body say me what libs use postgres for make system calls, for
> example LIBC?
>
> 2-Can any body talk me if some postgres process can run in Linux kernel
> space?
>
> 3- Some body knows if exist some projects that ports postgres process on
> Linux kernel space.
>
>
> I was read some source code of postgres, like,
>
> Postgres.C and others…
>
> I was found C instructions like Printf, that’s prohibitive for Linux
> kernel applications, for example in kernel mode we use printk.
>
> I suppose that postgres are ported in a user space only. I’m Ok?
>
>
> Thanks
>
> Moises

You can do it (e.g. http://www.yl.is.s.u-tokyo.ac.jp/~tosh/kml/) but why
would you want to? PG runs fine in userspace and I can see no particular
benefit to being in the kernel.

What exactly are you trying to do with it? Are you trying to interface
PG with some kernel facility?