Re: How fast is Oracle ?

The apparently excessive log writing activity you noticed could have been caused by log_buffer being set too small in your startup parameter file (init.ora file). Setting log_buffer to 131072 or even higher is not unreasonable.

Can any of the work be parallelized? In other words, are the 300 updates per second necessarily serial, done by one process? Or can the incoming data stream be split into multiple streams to be executed in parallel? If this is possible, then keeping different processes from trying to modify the same rows at the same time will be crucial, as will tuning Oracle to avoid contention on things like latches, rollback segments, etc.

I hope this helps...

   -Kevin J

In article <pirRZCAsqTGxEw6O_at_juno.demon.co.uk>, Richard Armstrong <richard_at_juno.demon.co.uk> wrote:

> Can anybody suggest a rough estimate of the speed of Oracle 7.1 ? The
> company I work for is considering Oracle for the development of a real
> time system to record share price data. It needs to be able to receive
> about 300 data items per second from an external source and update
> corresponding records in an Oracle table (ie 300 update statements per
> second). The table has three integer fields. One field is changed on
> each update. Changes are committed after every hundred updates.
>
> We have written a test application using a DEC Alpha machine running
> OpenVMS 6.1 and Oracle 7.1. The application is written in Pro*Pascal
> and it can only manage around 20 or 30 updates per second. We don't
> know whether this is the maximum rate we can reasonably expect or
> whether further tuning effort is likely to yield improvements.
>
> We did notice a great deal of disk access by the log writer process
> which seemed to slow things down. Should this process only write after
> a COMMIT ? We have tried speaking to Oracle support in the UK but they
> have not been able to offer much help. We are now considering trying
> other databases such as Ingres to see how they compare.
>
> I will be very interested to receive any thoughts or comments anybody
> may have.
> --
> Richard
 

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