tuning Postgres for large data import (using Copy from)

Hello,

I'd like to tune Postgres for large data import (using Copy from).

here are a few steps already done:

1) use 3 different disks for:

-1: source data
-2: index tablespaces
-3: data tablespaces


2) define all foreign keys as initially deferred

3) tune some parameters:

max_connections =20
shared_buffers =30000
work_mem = 8192
maintenance_work_mem = 32768
checkpoint_segments = 12

(I also modified the kernel accordingly)

4) runs VACUUM regulary

The server runs RedHat and has 1GB RAM

In the production (which may run on a better server), I plan to:

- import a few millions rows per day,
- keep up to ca 100 millions rows in the db
- delete older data

I've seen a few posting on hash/btree indexes, which say that hash index do
not work very well in Postgres;
currently, I only use btree indexes. Could I gain performances whole using
hash indexes as well ?

How does Postgres handle concurrent copy from on: same table / different
tables ?

I'd be glad on any further suggestion on how to further increase my
performances.

Marc

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