On Wed, 2008-07-02 at 09:58 -0400, Andrew Sullivan wrote:
> So I recommend against such a script.  Slony does it the way it does because
> of safety: it's trying to protect you, and this is the only reliable way to
> do it.  If you can be sure you have a case where you don't need that
> protection, then by careful use of the bare metal functions (which is how
> Slony does its work, after all) you can do this with less protection.

But that's a lot messier and riskier than having a script with a few
clear instructions in what circumstances it can work, and maybe a few
checks to enforce those circumstances are met (e.g. it must be a way to
figure out in a programmatic way if there are any FKs to/from that
table). It would also be relatively easy to enforce that the SQL to be
applied is just 1 statement which only touches 1 table...

The alternatives for me are:

 - keep watching my DBs for the moment I can sneak in a full DB lock
without breaking too many things (we managed to grow ourselves to the
point we have a pretty round the clock operation which is really always
busy);

 - study the bare metal functions you're talking about and cross my
fingers it wont kill my DB;

Both of these alternatives are very uncomfortable to me. Any script
which gets some testing would be a lot safer and welcome...

Cheers,
Csaba.