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 


-----Inline Attachment Follows-----

_______________________________________________
Slony1-general mailing list
Slony1-general at lists.slony.info
<http://us.mc530.mail.yahoo.com/mc/compose?to=Slony1-general@lists.slony
.info> 
http://lists.slony.info/mailman/listinfo/slony1-general

>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 





 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.slony.info/pipermail/slony1-general/attachments/20100224/3b9a0638/attachment.htm