Performance question (stripped down the problem)

Hello once more,

I stripped the database down to one single table with only the relevant
columns.  A pg_dump can be found under

    http://www.foodborne-net.de/~tillea/ifsg/ifsgtest.dump.bz2

I would really like it if you try the query


#!/bin/sh
ERG=$0.ptk
START=`date +%s`

echo "SELECT Hauptdaten_Fall.MeldeKategorie, Count(Hauptdaten_Fall.ID) AS Anz FROM Hauptdaten_Fall WHERE
(((Hauptdaten_Fall.IstAktuell)=20))GROUP BY Hauptdaten_Fall.MeldeKategorie ORDER BY Hauptdaten_Fall.MeldeKategorie;" |
psqlifsgtest > result 

let i="`date +%s` - $START"
echo "Query took ${i} seconds." >> result


(which should just measure the time needed for this task).  It took my
E250 (2x400MHz, 2GB) server 20 seconds and this is definitely much to
long for our application.

Any hints are gratly appreciated

         Andreas.