Re: Slony uninstall info/warning

John Sidney-Woollett wrote:
> Hopefully this will prevent data loss or problems for others using slony
> 1.0.5 and pg 7.4.6...
>
> We just got bitten by something we didn't foresee when completely
> uninstalling a slony replication cluster from the master and slave...
>
> MAKE SURE YOU STOP YOUR APPLICATION RUNNING AGAINST YOUR MASTER DATABASE
> WHEN REMOVING THE WHOLE SLONY CLUSTER, or at least re-cycle all your
> open connections after the event!
>
> The connections appear to "remember" or refer to objects which are
> removed by the uninstall node script. And you get lots of errors as a
> result (and possible data loss??)...
>
> Question: Why do our database objects still refer to removed slony
> objects after they are removed?

Well, there are two areas I know cache plans/OIDs:
1. Prepared statements
2. plpgsql functions

At a guess, since you mention Java the first almost certainly applies to
you.

This isn't a slony issue so much as a cached plan issue. I'm guessing
the same problems would occur if you were manually changing the database
schema.

Don't think you could get data loss (unless the application ignores
errors). You will however get to see a wide range of OID related errors.

--
Richard Huxton
Archonet Ltd