Re: multiple performance

On Apr 19, 9:36 am, Robert Klemme <shortcut..._at_googlemail.com> wrote:
> On 19.04.2007 15:14, Alexander Smirnov wrote:
>
> > Theoretical question.
>
> > For example
>
> > 1) 10 sessions, each in its own thread, each connected to the same
> > database and executes 10 updates on the same table, each update
> > affects 1 row.
>
> The same row or different rows?
>
> > 2) 1 session in one thread executes 100 updates on the same table,
> > each update affects 1 row.
>
> > What is faster?
>
> Practical answer: my Seat Leon.
>
> Seriously: I don't know what others will tell you but I can imagine
> situations where either is faster.
>
> Regards
>
> robert

Define faster. Is faster based on just the clock time from the start of the update process to the completion of the process or does it include the total run time of all 10 sessions verse the one?

If my choice is to run one session and perform 100 updates followed by one commit verse splitting the data into 10 units of work, starting a session for each unit, having the session perform the work, commit, and return a completion indication to the master process then I would probably choose to use one session for simple updates since 100 is a pretty small number. In this case the overhead would probably far exceed the gain. Because there are a great many details and performance issues to consider for each time you think you want to do this I would rely on the Oracle PQO feature to determine if a task should be ran parallel.

HTH -- Mark D Powell -- Received on Thu Apr 19 2007 - 09:43:20 CDT