Skip site navigation (1) Skip section navigation (2)

Re: [HACKERS] Threads vs Processes

From: "Dann Corbit" <DCorbit(at)connx(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>,"Bruce Momjian" <pgman(at)candle(dot)pha(dot)pa(dot)us>
Cc: "Shridhar Daithankar" <shridhar_daithankar(at)persistent(dot)co(dot)in>,<pgsql-hackers(at)postgresql(dot)org>, <pgsql-hackers-win32(at)postgresql(dot)org>
Subject: Re: [HACKERS] Threads vs Processes
Date: 2003-09-26 18:12:06
Message-ID: D90A5A6C612A39408103E6ECDD77B829408BCA@voyager.corporate.connx.com (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-hackers-win32
> -----Original Message-----
> From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us] 
> Sent: Friday, September 26, 2003 9:27 AM
> To: Bruce Momjian
> Cc: Shridhar Daithankar; pgsql-hackers(at)postgresql(dot)org; 
> pgsql-hackers-win32(at)postgresql(dot)org
> Subject: Re: [HACKERS] Threads vs Processes 
> 
> 
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > One solution is for me to continue with this in the Win32 
> CVS version 
> > until I have fork/exec() working on Unix, then test on 
> Win32.  I think 
> > that could be done in a few weeks, if not less.
> 
> > Another solution, already mentioned, is to use threads and 
> TLS.  This 
> > is what SRA's code uses.  I know SRA wants to contribute that code 
> > back to the community, so I can ask them to see if they are 
> ready to 
> > release it.
> 
> If you are willing to expend the effort, I think it would be 
> worth the time to pursue both approaches.  We don't yet have 
> enough info to decide which one will be cleaner, so we need 
> to push forward on both until we can make a realistic comparison.

I think the ideal situation would be a server that both threads and
forks.

Sometimes, we want the server to take on a new personality (with the
rights of the attaching user).  In such a case, threading is not a
sufficient answer.  Also, a forked process is a bit safer (though you
can put a try/catch around threads).

For performance with multiple queries from a single user, threads are
going to be faster than forking.  I think that the best model will be a
server that does both.

I know that there is some aversion to using C++, but the ACE framework
offers a consistent threading model that works for just about every
computer under the sun.
http://www.cs.wustl.edu/~schmidt/ACE.html

The license is basically BSD (it is called ACE, but it works exactly
like a BSD license).  With ACE, you program to a single API, and the
code works the same on every platform with a simple recompile.  It might
even be worthwhile to use the ACE higher level components to create a
server that supports multiple models of connection and threading.

pgsql-hackers by date

Next:From: Bruce MomjianDate: 2003-09-26 18:12:39
Subject: Re: initdb failure (was Re: [GENERAL] sequence's plpgsql)
Previous:From: Bruce MomjianDate: 2003-09-26 18:10:25
Subject: Re: 2-phase commit

pgsql-hackers-win32 by date

Next:From: Christopher Kings-LynneDate: 2003-09-27 05:20:22
Subject: Re: [HACKERS] Threads vs Processes
Previous:From: Bruce MomjianDate: 2003-09-26 16:35:40
Subject: Re: [HACKERS] Threads vs Processes

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group