Slow adding Large Indexes

Hi All,

I have recently moved postgres from one server to another (a newer
server) and have encounter a problem I cant figure out. I have a table
(roughly 7.5GB) that gets re-created every night with fresh data, to
insert the data I run the following procedure.

Drop all indexes
Truncate Table
Insert Data
Create Indexes

The problem I have is that it takes around 15 mins to insert the data
into the table which is a massive improvement from the old server but it
then takes 40 mins to create two indexes one 1GB index and another that
is a 2GB index this is considerably slower than on the older server.

I have had a play around with some of the settings but with no real
success, in particular the maintenance_work_mem setting. Any help on
this would be greatly appreciated. The new server is a Virtual Server
running RedHat Linux, Postgres 8.3 , 8GB of RAM with 4 x 2.66ghz. The
current settings in postgresql.conf I have are

shared_buffers = 768MB

temp_buffers = 100MB
#max_prepared_transactions = 5
work_mem = 64MB
maintenance_work_mem = 800MB
#max_stack_depth = 2MB

# - Free Space Map -

max_fsm_pages = 2097152
#max_fsm_relations = 1000

# - Kernel Resource Usage -

#max_files_per_process = 1000
#shared_preload_libraries = ''

# - Cost-Based Vacuum Delay -

#vacuum_cost_delay = 0
#vacuum_cost_page_hit = 1
#vacuum_cost_page_miss = 10
#vacuum_cost_page_dirty = 20
#vacuum_cost_limit = 200

# - Background Writer -

#bgwriter_delay = 200ms
#bgwriter_lru_maxpages = 100
#bgwriter_lru_multiplier = 2.0

/etc/sysctl.conf

kernel.shmmax = 4294967295
kernel.shmall = 268435456

Any help would be greatly appreciated, thanks in advance

Fran

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