Re: general peformance question

On Thu, 18 Dec 2003, Conny Thimren wrote:

> Hi,
> This a kind of newbie-question. I've been using Postgres for a long time in a low transction environment - and it is
great.
>
> Now I've got an inquiry for using Postgresql in a heavy-load on-line system. This system must handle something like
20questions per sec with a response time at 1/10 sec. Each question will result in approx 5-6 reads and a couple of
updates.
> Anybody have a feeling if this is realistic on a Intelbased Linux server with Postgresql. Ofcourse I know that this
istoo little info for an exact answer but - as I said - maybe someone can give a hint if it's possible. Maybe someone
withheavy-load can give an example of what is possible... 

That really depends on how heavy each query is, so it's hard to say from
what little you've given us.

If you are doing simple banking style transactions, then you can easily
handle this load, if you are talking a simple shopping cart, ditto, if,
however, you are talking about queries that run 4 or 5 tables with
millions of rows againts each other, you're gonna have to test it
yourself.

With the autovacuum daemon running, I ran a test overnight of pgbench
(more for general purpose burn in than anything else)

pgbench -i -s 100
pgbench -c 50 -t 250000

that's 10 million transactions, and it took just over twelve hours to
complete at 220+ transactions per second.

so, for financials, you're likely to find it easy to meet your target.
But as the tables get bigger / more complex / more interconnected you'll
see a drop in performance.