>> It is the same to the user either way. In either case you have to
>> change some settings and restart the master.
>
> Except that changing wal_keep_segments doesn't require restarting the master.
Our docs say that it does:
This parameter can only be set in the postgresql.conf file or on the
server command line.
http://www.postgresql.org/docs/9.0/static/runtime-config-wal.html#RUNTIME-CONFIG-REPLICATION
-- -- Josh Berkus PostgreSQL Experts Inc.
http://www.pgexperts.com