On 03/04/2004 04:20:24 PM, Tanel Põder wrote:
> > Is that good or bad? That depends on your site. Mixed mode OLTP/DSS/Batch
> > sites are a losing proposition any way you look at them. Having data guard
> > replicate your reporting tables to an operational data store and then
> > running reports from ODS is much better solution.
>
> In mixed environments I've often used a loggon trigger, which sets
> optimizer_* parameters and also sort & hash_area_sizes differently for large
> batch jobs based on username or whatever session attribute..
>
> Tanel.
>
Well, a big report running a hash join of two tables, one of which is big
will consume significant part of I/O bandwidth, significant part of CPU capacity,
it will speed up cycling of db_block_buffers, thus increasing the number of
I/O requests by the OLTP jobs and will make just about everything else run
significantly slower. That means that the effort invested in tuning OLTP
apps must be much larger, because every little mistake in application
design will slow users to unacceptable levels and then phones start ringing....
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Received on Thu Mar 04 2004 - 17:51:26 CST
