Re: How to avoid using the execution plan with parallel on oracle rac 19.13?

On 5/26/23 09:53, Andy Sayer wrote:
> There looks to be opportunity to tune that SQL, you’re going to the
> same gv$ view in your with clause (with a distinct and analytics) as
> you’re joining to later, presumably you should be able to just do the
> analytics in one go.
>
> Either way, this is a gv$ so needs to check each instance, so you get
> a parallel thread per instance.
>
> Why is a query against a gv$ view (which should be in memory on each
> instance) consuming IO?
>
> Thanks,
> Andy

Andy is right. Using GV$ tables always implies using parallel query because Oracle has to check every instance in the cluster. If you set "parallel_max_servers" to 0 on any cluster instance, you will disable access to GV$ tables.

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Mladen Gogala
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https://dbwhisperer.wordpress.com

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