Sorry for the delay.
I want to thank the brighton and hove python users group for the great evening.
As I promised here's the view to get the dead files on the PGDATA.
Dead files are files not mapped in the pg_class system table.
They can be present if any new file generation is interrupted by a crash recovery where the wal replay rollback the system catalogue operation but not delete the new files.
Not sure if this is a bug.
Anyway this is the code on pastebin.
Please be aware the view is specific for PostgreSQL 9.2. I'll try to build a self adapting version sooner or later.
As I had some interest in PostgreSQL I've started a simple google group, the sea elephants, for aggregating PostgreSQL users in the Brighton and Hove area.
I know there's a national usergroup (or some sort of it) but in my humble experience, local is better.
Because it's better to start from the little things, like a good beer in a lovely pub.
And yes this is an hint for the first meeting ever.