On Wednesday 24 February 2010 11:13:19 Walter Coole wrote:
> Dave's points are valid, but I'd suggest a tweak that I've found useful:
> use one of pg_dump's ascii modes, keep the pg_dump output and use rsync
> to do the copy to the laptop.  If the updates are rare and small, rsync
> (or a similar tool) will be much more efficient at doing the copy, at
> the cost of keeping an extra copy of the database on the laptop.
> 
> 
> 
> I found that, for my installation, this arrangement was easier to set up
> and maintain than Slony or any of the other replication schemes for
> Postgres.
> 
> Walter
> 
> 
> 
> From: slony1-general-bounces at lists.slony.info
> [mailto:slony1-general-bounces at lists.slony.info] On Behalf Of Melvin
> Davidson
> Sent: Wednesday, February 24, 2010 9:44 AM
> To: Slony1-general at lists.slony.info; Dave Stevenson
> Subject: Re: [Slony1-general] Is Slony for me?
> 
> 
> 
> --- On Wed, 2/24/10, Dave Stevenson <dave.stevenson at pacbell.net> wrote:
> 
> From: Dave Stevenson <dave.stevenson at pacbell.net>
> Subject: [Slony1-general] Is Slony for me?
> To: Slony1-general at lists.slony.info
> Date: Wednesday, February 24, 2010, 11:28 AM
> 
> I'm looking for a replication solution, but I'm no DBA. My use case is
> probably similar to the following, listed in Slony's online doc as a
> poor match for Slony:
> 
>     Replicating a pricing database from a central server to sales staff
> who connect periodically to grab updates.
> 
> 
> 
> I'm wondering what is it about Slony that makes that scenario a bad
> match, or what alternative might work better for me.
> 
> 
> 
> I use Postgresql as a source code repository. However, the server is
> remote, and access is typically very slow. I'd like to have a read-only
> local copy for comparing, reconciling, loading, etc., and access the
> remote server only for writes (publish). Typical usage is lots of reads,
> few writes, very rare and limited updates, even more rare and limited
> deletes (few times per year?), and maybe once every 2-4 years a schema
> change.
> 
> 
> 
> If I have a local clone on my laptop, it will often be offline (at
> night). Is Slony a bad match because the slave would miss updates while
> offline?
> 
> 
> 
> Anyone know of a better fit for my use case?
> 
> 
> 
> Thanks,
> 
> 
> Dave Stevenson
> dave.stevenson at pacbell.net
> 
> 
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> 
> >I'd like to have a read-only local copy for comparing, reconciling,
> 
> loading,
> 
> >etc.
> 
> Good news. Slony is excellent for that situation.
> 
> >If I have a local clone on my laptop, it will often be offline (at
> 
> night). Is Slony a
> 
> >bad match because the slave would miss updates while offline?
> 
> Bad news.  Unless there is only a small amount of updates (DML) that
> will be occurring while your laptop is offline, it will take a long time
> for slony to synchronize and catch up with transactions that occurred.
> If your database is small enough, you might be better off just doing a
> pg_dump of the master, and then copy it to the laptop, drop the old
> database, make a new db  and then pg_restore the new copy.
> 
> Melvin Davidson
> 


This scenario is actually a perfect fit for SLONY log shipping which would 
allow your laptop to act as a 'remote' or 'disconnected' subscriber thus 
you'll be able to have your laptop apply the slon logs on any schedule you 
decide.