Too much RAM allocated by webserver when executing an Insert-Statement (npgsql)

Hi list,

I am using Npgsql to connect from a webapplication to a PostgreSQL Database.
When I insert one row into a table (containing a filestream converted to
bytea) the webserver allocates too much RAM for the webserver process
(around 80MB when uploading a 4 MB file) and does not deallocate the RAM
after executing the statement and closing the connection.

I know this is not directly related to PostgreSQL, but maybe someone of you
has already has this behaviour and has some hints for me how to make the
webserver not allocate as much space or at least deallocate the RAM after
finishing the insert statement.

The Npgsql statement that causes this is:

insertstatement.ExecuteNonQuery()

Unfortunately I could not yet get any help in the Npgsql forums, maybe you
can help me out.

I'd be grateful for any help.

Chris