The databases I am replicating have around 200 sequences.  To replicate 
these with slony or our modified dbmirror, that means we require 200 select 
queries at every sync interval.  That can be a significant load in our case 
if we want short sync intervals.  It'd sure be nice if there were another 
way so that we didn't have to poll so many relations.  This leads me to the 
thought of having triggers on sequences, which I know does not exist at 
present in pgsql.

Jan, you know a lot about PostgreSQL internals, maybe others here do as 
well.  Are triggers on sequences a reasonable feature request/hope for 
Pgsql?  Short of simply increasing the sync interval, what other options 
are there for addressing the performance load?

Ed