Thank you, I'll try your suggestions.
I'm just slow in doing so, because it's just a
(sometimes pretty time consuming) hobby-project.
I'm missing knowledge on how to monitor my DB status,
i.e. how to check some of the things you've asked.
Also I wonder, how's shared memory used by PostgreSQL.
I'm irritated - how it could work with 32MB,
but now I've got suggestion to increase it
to 512MB (and it seems to work too...)
Regards
Alex