Scaling PostgreSQL-9

Hello All,

Need some help in scaling PostgreSQL:

I have a table with 400M records with 5 int columns having index only on 1 column.

Rows are updated by a perl script which takes 10k numbers in one transactions and fires single single update in a loop on database keeping track of the result returned . If zero returned then at later stage it does an insert. In short if the record is present in the DB then it gets updated and if not then get inserted. > 80% the records are always there in the DB so updates are more.

We need to speed up this process as it takes about 150 sec to complete 10k batch. From database logs on the avg each update takes about 15ms.

I tried to do a bulk delete of 1M numbers and copy of the same but no luck so far. Delete and copy also take a longer time more than 1 hour each.

Few Details:

PostgreSQL 9.0.0 on 11.0 open SuSe-64bit,Shared buffer=2.5GB,effective_cache_size=20GB,checkpoint_segments=200 (raised for bulkloading)

Server: dell dual quadcore ,32GB RAM, DB partition on RAID 10 and pg_xlog on RAID 1.

p.s. Previously we were having slony read only slave on 8.4.2 , where delete was fast about 7 min and copy 6 min, we moved to PostgreSQL 9 for read only Stand by slave to remove overhead caused by slony due to triggers (also the slave was always lagging in case of bulkloads on master)  in the hope of speeding up the process.

Any help would be much appriciated ...

With Regards
sandy