Database performance problems

Dear all,

I have been using Postgres but I am not an expert on the subject.

I would be very grateful if someone could point to the right direction with regards this problem.

We have a web application written in JAVA, using jaboss as a servlet.

There are 100 connections open to the database server at any given time, apparently using hibernate.

We are using Postgres 8.2.4 compiled

The database size is 155GB

We have 8GB of RAM

300GB Hard disk Raid1

Everything is within a single Volume

Today the load average was as high as 15

Top result:

Tasks: 169 total,  30 running, 139 sleeping,   0 stopped,   0 zombie

Cpu(s): 69.6% us,  5.9% sy,  0.0% ni,  0.0% id, 24.3% wa,  0.2% hi,  0.0% si

Mem:   8251404k total,  8228428k used,    22976k free,    16296k buffers

Swap:  1052248k total,    47176k used,  1005072k free,  6664308k cached

I am quite sure:

1 – we do not have enough memory

2 – our disk and RAID array setup is not good enough

3 – Postgres is not setup correctly and uses an older version

4 – It is using Slony and replication which does not work.

I would like if anyone could help with the following:

1 – Ways of proving my thoughts

2 – Gather data evidence to prove

I don’t have slow query check enabled, will do after Christmas, but how can I use it to show things are not good?

If anyone could help me it would be very much appreciated.

If you need more info or details, I am very happy to give more.

Thank you very much

Best regards

Renato Oliveira