James Dey wrote:
Apologies if this is a novice queston, but I think it is a performance one
nevertheless. We are running a prototype of a system running on
PHP/Postgresql on an Intel Xeon 2ghz server, 1GB RAM, 40GB hard drive, as a
test bench. The system will be used for tens of thousands of users, and at
the moment we are testing on a base of around 400 users concurrently during
the day.
OK, that's 400 web-users, so presumably a fraction of that for
concurrent database connections.
During the day, the system is incredibly slow to a point where it is
unusable. The reason we are testing on such as small server is to test
performance under pressure, and my estimation is that spec should handle
thousands of users.
It'll depend on what the users are doing
It'll depend on what your code is doing
It'll depend on how you've configured PostgreSQL.
The server spikes from 5% usage to 95% up and down.
Usage? Do you mean CPU?
> The system is a very
simple e-learning and management system and has not given us any issues to
date, only since we've been testing with more users has it done so. The fact
that 400 users doing inserts and queries every few minutes is very
concerning, I would like to know if I could be tweaking some config
settings.
You haven't said what config settings you're working with.
OK - the main questions have to be:
1. Are you limited by CPU, memory or disk i/o?
2. Are you happy your config settings are good?
How do you know?
3. Are there particular queries that are causing the problem, or lock
contention?
We are running PG 7.4 on a Debian Sarge server, and will be upgrading to
pg8.0 on a new server, but have some migration issues (that's for another
list!)
Go straight to 8.1 - no point in upgrading half-way. If you don't like
compiling from source it's in backports.org
--
Richard Huxton
Archonet Ltd
