Re: When to run batch in parallel?

But if you have resources and doing FTS of large table then parallel can be very helpful.

On Mon, May 24, 2010 at 1:14 PM, Charlotte Hammond < charlottejanehammond_at_yahoo.com> wrote:

> We've got a long running batch job. Tracing shows 95% of the time is I/O
> waits (mostly scattered reads steming from hash joins) against our SAN. Our
> architect wants to split it into several parallel streams but I'm dubious.
> Surely the SAN won't serve up data any faster just because we're running in
> parallel.
>
> Is there any benefit in this strategy? I would expect parallelism to come
> into play if there's significant non-I/O time (e.g. busy on CPU) where other
> sessions could take advantage of the burstiness, or if the database was
> accessing multiple disks directly, not virtualised over a big SAN cache. I
> reckon we just need a faster SAN (and/or some SQL tuning).
>
> Any comments?
>
> Many thanks
> Charlotte
>
>
>
>
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>

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Thanks & Regards,
Taral Desai

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