database is growing... 1GB per day basis

Hello, my name is raghu. I work for Avaya. We uses postgres as database
in our application. Our application is a jboss based enterprise
application, that does some updates operations based on requests from
client. We use entities and hibernate for data access within our
application.

I have couple of questions, as listed:

1. We observe that database is growing very fast - many sets of
files with size more than 1 GB. Please see some sample snippets of the
file lists:

This does not happen regular basis. However, we have a few instances of
this incidence, and pretty much blocked on this. What could be causing
this? What can be done to diagnose/ resolve this issue? We are running
out of disk space in our box quite quickly due to this issue. Any
thoughts please?

2. One of our table has columns for LOB. All other tables are of
primary types (there are a few sting/ varchar types as well). I
understand that postgres maintains large data objects in pg_largeobject.
Is there a way to find the data within those table? How can I find out
the corresponding table information or row corresponding to this large
data maintained/ managed in pg_largeobject? I also hear about
pg_toast... wot is the relation between pg_toast and pg_largeobject?

I would appreciate your early response and help very much!

thanks/ regards,

raghu