> OK I thought there might have been a 'dry run' in a BEGIN/ROLLBACK block which watched which tables were being affected. Is this kind of thing planned for a future release?

Well, if your script adds a column with default value to a huge table I
guess you wouldn't want a dry run first ;-) I certainly won't like slony
doing that by default.

> That I don't understand, because I specified the script to run on set 2, but I am only seeing deadlocks on tables which are only in set 1! :(

OK, then is it possible that your script affects those tables outside
the set ? It is possible for example if you modify foreign key relations
which point outside the set. That's why the slony docs state pretty
clearly you should stuff all tables related by FKs into the same set...

Cheers,
Csaba.