rubyrep breaks Silver Stripe (MVC frame work) and vis versa.

Lists: pgsql-general
From: Gregory Machin <gdm(at)linuxpro(dot)co(dot)za>
To: pgsql-general(at)postgresql(dot)org
Subject: rubyrep breaks Silver Stripe (MVC frame work) and vis versa.
Date: 2011-01-20 06:49:04
Message-ID: AANLkTi=ES3Lvto1NhhYxzyyyRZASAmfuMKA=ZvKfwQP_@mail.gmail.com
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Lists: pgsql-general

Hi.
I'm new to Postgresql, database replication and Silver Stripe.

I have to provide a solution for real time database replication. I was
using Rubyrep to do replication to a second database running as Hot
standby / Master-Master. The developers failed to tell me that you
can't use trigger based replication with a MVC frame work like Silver
Stripe. After deploying new code / patched one must run a dev/build ,
which kicks of a process that rebuilds and adds to that database. This
causes triggers to go missing and other things associated to Rubyrep
to break. This resulted it corrupted data. And 2 days of work to fix
it.

Can some one suggest a replication solution. We are using a F5
appliance to provide fail over between 2 Postgresql 8.4.4 servers. It
is currently configured to do a tcp connect to validate that primary
server is up, if it can't reach the primary to switch to the
secondary, thus real time replication and the secondary server being
immediately available is critical. (later it's to be configured to
query the database directly to validate that it is truly available.).

I was looking at DRBD solutions but currently the network is
configured such that multicast is not allowed and can not be
reconfigured for the next couple of months until an outage can be
scheduled.

In short how can I get "Hot standby" / master-master replication that
will be transparent to the changes made by Silver Stripe, that will
work with Postgresql 8.4.4.

Thanks
G


From: Vick Khera <vivek(at)khera(dot)org>
To: pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: Re: rubyrep breaks Silver Stripe (MVC frame work) and vis versa.
Date: 2011-01-20 15:57:05
Message-ID: AANLkTimgcA0xWTLNUVLWBQ3K=MWLqPdoHo43O13b9_tq@mail.gmail.com
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On Thu, Jan 20, 2011 at 1:49 AM, Gregory Machin <gdm(at)linuxpro(dot)co(dot)za> wrote:
> In short how can I get "Hot standby" / master-master replication that
> will be transparent to the changes made by Silver Stripe, that will
> work with Postgresql 8.4.4.
>

The only replication system I know of that does not need to be aware
of the schema structure (and therefore must be aware of changes made
to it) is the hot standby built into postgres. However, that does not
get you master/master which you seem to want.

I do not think your set of requirements can all be fulfilled. You
will have to adjust one or more of them. I'll venture to say that the
best target is to adjust the ORM's "update" process to be aware of
your replication strategy, and work with it rather than assume it has
full control over the DB.