COPY slows down; is it normal?

Hi,

I am watching the progress of a COPY from a 2 megarow table. It seems to slow down almost exponentially. The database
filegrew at about 2 megabytes a minute in the beginning and now, 20 hours since started, it grows at 80 kilobytes a
minute.The table has 7 columns of char and int types, the last column is text. The scene is a dual 400MHz i586 running
RedHat5.1 and postgres 6.3.2, as originally distributed, no patches. As far as I can tell by 'tail | strings | tail' on
thedatabase file, it is more than halfway there, but such exponential slowdown makes me anxious. Other users will have
totake vacation: 

  PID USER     PRI  NI  SIZE  RSS SHARE STAT  LIB %CPU %MEM   TIME COMMAND
14778 postgres  10   0  2840 2588  2124 R       0 98.2  1.0  1273m postgres


Last time I tried to load the same table without the last column, COPY took 4 hours and hash on one of the columns took
7.

Is there any room for improvement?

Thanks,

Gene