[rt-users] Performance on PostgreSQL

[Kevin White]

We have an install of RT running on Linux/PostgreSQL, and it seems slow 
to me.

For example, if I just bring up a ticket:

http://xxx/index.html?q=58431

the little Time to display can be anywhere between 3.6 and 8.  It tends 
to the longer side of things.

My overall question is: what's good?  What should I expect?

Now, the Too Much Information part of my post:

First things first: the Fedora4Install page mentions a missing index. 
I've created that, but it doesn't seem to have changed things much.

The production server is running Centos 4 (RHEL 4) on a machine that 
really doesn't have enough RAM (1GB) and only has IDE disks, running as 
a software RAID1.  It IS an Opteron, and it is running 64-bit.  rt 3.4.1 
and postgresql 8.0.3.

Suspicions: disk I/O, and a suboptimal Apache/mod_perl install. 
However, when things are happening slowing, what I see in top is postmaster.

So, I have a newer box.  I decided to copy rt and my database over to it 
to see how it acts.  It is a faster Athlon 64 and 2GB, but still has IDE 
disks running in a software RAID 1.  It is running Fedora Core 5, so it 
has a better apache/mod_perl chain, and postgresql 8.1.4.  After finally 
getting rt (still 3.4.1) running on this new box, the performance wasn't 
markedly better...sometimes, it could be worse.  I followed the tips in 
the FedoraCore4 install instructions to increase shmem and the 
shared_buffers, to no real benefit.

So, I'm kind of looking for data points as to how good this can be, to 
see how much more work I should put into this.  Do I need 2 tiers?  Do I 
need to get rid of the software RAID?  (Although, the performance I see 
out of Dell's SCSI hardware RAID stuff is abysmal...)

I have another Athlon 64 box I can try that doesn't have software RAID 
on it...I'm just trying to decide if it is worth it, or if I'm getting 
the best I can hope for.

I've even considered seeing if I can move to MySQL, but the info on the 
Wiki seems to hint that both can perform well.

Any hints as to what I can expect for performance, or what I should be 
looking at to see if I'm actually having problems, or how to tell where 
the hang-ups might be, are welcome.

Thanks,

Kevin