> I can't find any doc's on what happens to replication data collected by
> triggers -
>
> 1) when will it be deleted (both on master and on replicating slaves)
> 2) in what cases is it kept on slave side

Loosely speaking, it is deleted until it is not needed anymore by any of
the subscribers for a given node.

But that's too loose an answer; I haven't started rummaging through the
criteria slon uses for this, which I _do_ care about...  It's not in the
documentation at this point; you will have to look directly to the slon
code.