From: Mendola Gaetano <mendola@bigfoot.com>
To: Diehl, Jeffrey <jdiehl@sandia.gov>
To: 'Michael A Nachbaur' <mike@nachbaur.com>
To: pgsql-sql@postgresql.org
Subject: Re: pgsql Replication Proxy (was Re: Replication for a
Date: Tue, 6 May 2003 19:54:41 +0200
Message-ID: <000e01c313f8$941ef5e0$10d4a8c0@mm.eutelsat.org> (raw)
References: <B51F0C636E578A4E832D3958690CD73E0130C42C@es04snlnt.sandia.gov>
Postgres don't have the support ( yet ) for the 2 phase commit, so
I think that is impossible do it now.
What happen if the last server do an error in commit phase ?
Regards
Gaetano
----- Original Message -----
From: "Diehl, Jeffrey" <jdiehl@sandia.gov>
To: "'Michael A Nachbaur'" <mike@nachbaur.com>; <pgsql-sql@postgresql.org>
Sent: Tuesday, May 06, 2003 6:28 PM
Subject: Re: pgsql Replication Proxy (was Re: [SQL] Replication for a
> I love this idea. The proxy could return immediately instead of making my
> program block on update.
>
> One note, though. Instead of a stack, you need a FIFO. For example:
>
> delete from sometable where field=value;
> insert into sometable (field) values (value1);
> insert into sometable (field) values (value2);
> ....
>
>
> This code breaks in a stack and only works in a fifo. Minor point,
though.
>
> So do we have a volunteer to write such a tool? <grin>
>
> Mike Diehl.
>
> -----Original Message-----
> From: Michael A Nachbaur [mailto:mike@nachbaur.com]
> Sent: Monday, May 05, 2003 1:57 PM
> To: pgsql-sql@postgresql.org
> Subject: pgsql Replication Proxy (was Re: [SQL] Replication for a large
> database)
>
>
> I've thought some more about this, and I want to pass this idea past you
> guys.
> What do you think about a replication proxy, essentially a daemon that
sits
> between a PostgreSQL client and server. Every single SQL query,
transaction
>
> statement, etc that the proxy recieves it repeats back to all the database
> servers. In this way, if a back-end database server goes down queries
will
> continue unabated (except the downed server won't recieve updates).
>
> Basically, the proxy server could intercept these queries and place them
in
> a
> stack (on a per-database basis) and when every server in the queue
> acknowledges the update, the query is removed from the stack. Each
database
>
> server can have their own position in the stack, so if servers A and B
> successfully run a query, but C doesn't (e.g. it requires human
> intervention), C is removed from the list of acceptable servers but A and
B
> can keep moving through the queue.
>
> What do you think? Also, should this discussion be moved to another
mailing
>
> list?
>
> On Monday 05 May 2003 12:26 pm, Michael A Nachbaur wrote:
> > I have thought about this. The problem I come into is data consistancy.
> I
> > have at least 8 different processes that harvest data, and an intranet
> > website that can also manipulate the database (to assign customers to
> > different packages, re-assign modems to different customers, etc).
Trying
> > to maintain consistancy across the entire application would be such a
> > nightmare, I don't want to think about it.
> >
> > If I go with a centralized middleware server that manages all database
> > access, then I could perhaps do that in there...and then I could use
> > transactions on both databases, and if either transaction fails then
I'll
> > roll back the other. But this would make my entire framework very
rigid.
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly
>
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: mendola@bigfoot.com, jdiehl@sandia.gov, mike@nachbaur.com
Subject: Re: pgsql Replication Proxy (was Re: Replication for a
In-Reply-To: <000e01c313f8$941ef5e0$10d4a8c0@mm.eutelsat.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox