Databases there, tables away

Hi,
I am concerned.
I played around with test database clusters of postgres. I wanted to
simulate a WAL-Replay. So what I did was:
I have a data dir, where some databases exist.
I stressed them to produce a couple of Wal files.
Then I shut down postgres  (SIGQUIT *hm*)
created + initdb'ed another dir
put the wal files in the pg_xlog
restarted the server on the new dir.
I made it wrong, so forget this dir and shut down postgres
So
restarting postgres on the former data directory lead to the
situation where all databases exist but with no objects populated. No table
no function. What can hav happened?

It is not do bar that someone else did something. But what can happen do a
data dir if postgres is run on another dir?


There's nothing lost, but I want to unterstand that