I have noticed a scenario (whilst running DDL tests) which causes me
to want to add an extra test to the pre-processing of this...

Suppose we have 3 nodes, and subscriptions have been requested for a
set on all 3 nodes.

Regrettably, due to some error having happened (deranged slon?), the
third node hasn't yet *successfully* subscribed to the set.

If I restart the slon for node #3, soon enough, all is well, and it
subscribes successfully.

If a DDL change comes through, before that time, that can (and will)
destroy the ability to do this.

The DDL change is successfully processed, and hits nodes 1 and 2.

If, at *THAT* point, I restart the slon for node #3, it tries
processing the original SUBSCRIBE SET event, only to discover that the
COPY output from the providers (which have taken account of the
EXECUTE SCRIPT request) have different schemas than node #3.  At which
point node #3 is screwed.  No reasonable fix possible short of
toasting it and recreating the node.

I propose to check to have EXECUTE SCRIPT fail if it discovers a
subscriber from which it does not have a recent confirmation.  (I have
yet to figure out the exact nature of the sl_confirm query; I'll wait
'til Monday on the off-chance that I might get to work and discover a
solution in my inbox ;-).)
-- 
(format nil "~S@~S" "cbbrowne" "ca.afilias.info")
<http://dba2.int.libertyrms.com/>
Christopher Browne
(416) 673-4124 (land)