Re: Effective compression ratio with minimal performance overhead

Thank you. Actually I read in many blogs(for e.g in below doc) stating there is "minimal performance overhead" with advanced compression, so this 100% degradation surprised me and thus wanted to check if this is expected behaviour or if I am checking it wrong. And at the same time , why is the HCC compression(compress for query low) experiencing zero performance overhead?

https://www.oracle.com/technetwork/database/options/compression/advanced-compression-wp-12c-1896128.pdf

On Mon, May 23, 2022 at 1:53 AM Mladen Gogala <gogala.mladen_at_gmail.com> wrote:

> On 5/22/22 15:31, Lok P wrote:
>
> With Advanced compression, a table of size ~500GB is reduced to ~100GB.
> But the execution time of a batch INSERT query (using a batch size of 100)
> is increased from ~6minutes to ~13minutes for 10million rows. And run time
> of a multi threaded 'UPDATE' using pipelined function has been increased
> from ~11minutes to ~29minutes. It was updating 16million rows.
>
> Well, there is no such thing as a free lunch. And thee is no such thing as
> cheap gasoline.
>
> --
> Mladen Gogala
> Database Consultant
> Tel: (347) 321-1217https://dbwhisperer.wordpress.com
>
> -- http://www.freelists.org/webpage/oracle-l

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