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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