I was faced with interesting problem. Which schema, in my DB, uses the most disk space? Theoretically it's trivial, we have set of helpful functions: pg_column_size pg_database_size pg_indexes_size ...

On 23rd of February, Heikki Linnakangas committed patch: Replace checkpoint_segments with min_wal_size and max_wal_size. Instead of having a single knob (checkpoint_segments) that both triggers checkpoints, and determines how many checkpoints to recycle, they are now separate concerns. There is still an internal variable called CheckpointSegments, ...