Re: database bloat, but vacuums are done, and fsm seems to be setup ok

Looks like it's definately an issue with index bloat. Note that it's
normal to have some amount of empty space depending on vacuum and update
frequency, so 15G -> 20G isn't terribly surprising. I would suggest
using pg_autovacuum instead of the continuous vacuum; it's very possible
that some of your tables need more frequent vacuuming than they're
getting now. If you go this route, you might want to change the default
settings a bit to make pg_autovacuum more agressive.

Also, I'd suggest posting to -hackers about the index bloat. Would you
be able to make a filesystem copy (ie: tar -cjf database.tar.bz2
$PGDATA) available? It might also be useful to keep an eye on index size
in pg_class.relpages and see exactly what indexes are bloating.