Thread: A question on performance

We are looking at the possibility of using postgresql as the DBMS for a web
based interface to our SCADA system. The design calls for snapping the real
time data base into postgresql which will then be accessed by a browser
based application to display the data on graphical displays.

The question we have is how fast is postgresql? based on current system
loadings and average sizes we can except anywhere from 700 to 900 updates
per second.
The data will sent to a server application on a different platform from what
the SCADA system is running. The record size for each transaction will be
somewhere around 25 bytes. We may be sending 1 ... N records per update
depending on the system loading. Is there an optimum number? I don't expect
N to 50 to 60 records.
We will try and determine an optimum buffer size to send to keep the queue
from backing up on the SCADA side.

Will postgresql be able to handle that many updates per second an a
sustained basis (24/7)?

Ron Harter
Ealanta Software LLC
rdh@ealanta.com

On Fri, Sep 13, 2002 at 03:33:01AM +0000, Ron Harter wrote:

> loadings and average sizes we can except anywhere from 700 to 900 updates
> per second.

> Will postgresql be able to handle that many updates per second an a
> sustained basis (24/7)?

You don't say what hardware you're planning on using.  So a definite
"maybe".  If your disk is fast enough and you have enough CPUs, you
should be able to handle it without too much trouble.  But if you're
planning on running it on an old Pentium box with 16 Meg of memory,
you'll have a rough time ;-)

A

--
----
Andrew Sullivan                         204-4141 Yonge Street
Liberty RMS                           Toronto, Ontario Canada
<andrew@libertyrms.info>                              M2P 2A8
                                         +1 416 646 3304 x110

On Mon, 16 Sep 2002, Andrew Sullivan wrote:

> On Fri, Sep 13, 2002 at 03:33:01AM +0000, Ron Harter wrote:
>
> > loadings and average sizes we can except anywhere from 700 to 900 updates
> > per second.
>
> > Will postgresql be able to handle that many updates per second an a
> > sustained basis (24/7)?
>
> You don't say what hardware you're planning on using.  So a definite
> "maybe".  If your disk is fast enough and you have enough CPUs, you
> should be able to handle it without too much trouble.  But if you're
> planning on running it on an old Pentium box with 16 Meg of memory,
> you'll have a rough time ;-)

Plus, if they're updates, not inserts, he's gonna need to schedule a
vacuum to run almost continuously in the background.  And he might wanna
look at moving the pg_xlog directory to another drive