As has been previously mentioned a couple of times, it should be
perfectly possible to use streaming replication to get around the
limitations of archive_command/archive_timeout to do log archiving for
PITR (being that you either keep archive_timeout high and risk data
loss or you set it very low and generate a huge log archive without
need).
I've put together a tool to do this. The basic idea is to just stream
down replication and write it to regular WAL files, which can then be
used for recovery. You'll still need to use archive_command together
with it to ensure that the backups are complete. Streaming replication
doesn't guarantee that - in fact, regular replication will fallback to
using whatever archive_command created when wal_keep_segments isn't
enough.
I've put up an early version of the tool at
http://github.com/mhagander/pg_streamrecv
Comments and contributions are most welcome. And frankly, a good
review is very much required before I'd trust it ;) Hopefully, I
didn't overlook something critical :D
--
Magnus Hagander
Me: http://www.hagander.net/
Work: http://www.redpill-linpro.com/