fwd: parallel PSQL ? - Mailing list pgsql-hackers

Forwarded from Mosix mailing-list.
Is this a crazy stuff?

Mosix isn't useful for shared memory processes (like apache and postgresql) 
it simply doesn't migrate such tasks.
You can do a simple connect script that , for example , do a
round-robin connection to the different postgresql servers on the machineS.

-----------------  $dbh = connect_do_db();
---------------
first time it connects to machine1, second time to machine2 ...machineN, 
than you re-start from 1, or you can poll the load of the machines and 
choose the less loaded machine.

Other points: start only one machine that init the shared mem structures 
(the first), not the others (is there a postgres flag to do this stuff). GFS 
doesn't implement fcntl that posgres uses a bit.
The file to patch is in backend/storage/ipc/ipc.c, just add IPC_DIPC in 
shmget and semget.

This is are my ideas, i've not yet done all the stuff.

If this perform ok, also other similar programs will perform ok.


bye
valter


>From: "Prescott, Richard (EXP)" <richard.prescott@lmco.com>
>To: mosix-list@cs.huji.ac.il
>Subject: RE: PSQL, Mosix is unuseful
>Date: Fri, 03 Nov 2000 14:07:22 -0500
>
>I just though about it.
>
>If you run DIPC + GFS + postgresql.  Where the clients will connect ?  I 
>mean.  There is more than one machine answering to postgresql port!  You 
>need to distribute the load.  and that's the whole point of Mosix: one 
>virtual machine!
>
>Richard
>
> > -----Original Message-----
> > From:    valter m [SMTP:maweb@hotmail.com]
> > Sent:    November 01, 2000 9:45 AM
> > To:    Netmaster@streetwise.se; mosix-list@cs.huji.ac.il
> > Subject:    Re: PSQL, Mosix is unuseful
> >
> > Hello everyone,
> >
> > no hope to use PostgreSQL + Mosix, because PostgreSQL uses shared 
>memory, as
> > such it's not suitable for migration.
> >
> > Mosix isn't able now to give us a single system image, where a cluster 
>of
> > machine acts as a single transparent machine.
> >
> > I'm trying DIPC+GFS to do this, i've patched the 2.2.17 linux kernel 
>with
> > DIPC , changed PostgreSQL sources to create distributed shared memory 
>and
> > semaphores (postgres uses only sem and shm), next steps are to try to
> > start-up (the changed) postgres to use this  distibuted ipc and a 
>central
> > location for datafiles (GFS , NFS?, or a thing that permits a shared fs 
>with
> > flock and fcntl) , then do a simple connect script that , for example , 
>do a
> > round-robin connection to the different postgresql servers on the 
>machineS.
> >
> > DIPC has not a failover mechanism now.
> >
> > Ideas?
> >
> > bye
> > valter
> >
> >
> >
> > >From: Johan Sj> �holm <Netmaster@streetwise.se>
> > >To: "Mosix List" <mosix-list@cs.huji.ac.il>
> > >Subject: PSQL
> > >Date: Wed, 1 Nov 2000 14:09:34 +0100
> > >
> > >Hello everyone,
> > >
> > >Anyone that has tryied PostgreesSQL under Mosix ? How well does it run 
>?
> > >Just checking before I get going whit it;)
> > >
> > >And I am also going to run Apache on those machines, will that work any
> > >good ?
> > >
> > >Whit friendly Regards
> > >
> > >- Johan
> > >
> > >
> > >--
> > >To unsubscribe, send message to mosix-list-request@cs.huji.ac.il
> > >with "unsubscribe" in the message body.
> > >
> >
> > 
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