Dont understand my performance problem - Mailing list pgsql-general

Hi,

does anybody known why this takes so long (> 2 seconds).

update Request set Feedback = r.Erzeugt + q.Alarm2
    from Request r, Queue q
    where r.Request_Id = 4312 and r.Queue_Id = q.Queue_Id;

There are indices on all relevant columns but Alarm2.

The tables are:

Table    = queue
+----------------------------------+----------------------------------+-------+
|              Field               |              Type                | Length|
+----------------------------------+----------------------------------+-------+
| queue_id                         | int4                             |     4 |
| name                             | varchar()                        |   128 |
| qtag                             | varchar()                        |    16 |
| absender                         | text                             |   var |
| adresse                          | text                             |   var |
| bearbeiter                       | varchar()                        |    16 |
| bearbeiter1                      | varchar()                        |    16 |
| bearbeiter2                      | varchar()                        |    16 |
| revisor                          | varchar()                        |    16 |
| revisor1                         | varchar()                        |    16 |
| revisor2                         | varchar()                        |    16 |
| alarm1                           | reltime                          |     4 |
| alarm2                           | reltime                          |     4 |
| sofort                           | bool                             |     1 |
| lastmoddate                      | abstime                          |     4 |
| lastmoduser                      | varchar()                        |    16 |
+----------------------------------+----------------------------------+-------+
indices on: queue_id, revisor, bearbeiter
total entries about 10

Table    = request
+----------------------------------+----------------------------------+-------+
|              Field               |              Type                | Length|
+----------------------------------+----------------------------------+-------+
| request_id                       | int4                             |     4 |
| erzeugt                          | abstime                          |     4 |
| bearbeitet                       | abstime                          |     4 |
| bearbeiter                       | varchar()                        |    16 |
| beschreibung                     | text                             |   var |
| status                           | int4                             |     4 |
| stadium                          | varchar()                        |    16 |
| level                            | int4                             |     4 |
| locked                           | bool                             |     1 |
| qtag                             | varchar()                        |    16 |
| queue_id                         | int4                             |     4 |
| priority                         | varchar()                        |    16 |
| sender                           | varchar()                        |   128 |
| lastmoddate                      | abstime                          |     4 |
| lastmoduser                      | varchar()                        |    16 |
| erstreaktion                     | abstime                          |     4 |
| feedback                         | abstime                          |     4 |
+----------------------------------+----------------------------------+-------+
indices on: request_id, queue_Id, Erzeugt, Erstreaktion, Feedback, some more
total entries about 4000

erstreaktion and feedback was added later using 'alter table add column...'

I did my vacuum on both tables recently.

Postgres Version 6.3.2

Any ideas?

\magnus