Re: Effective compression ratio with minimal performance overhead

Hi
Compression happens on the db nodes. That has been the case since the beginning and still is. As Johnathan said, decompression happens on the storage nodes when smart scan is done (and cpus are not overloaded as he mentioned). All this is done by software.

Regards

On Mon 23 May 2022 at 08:06, Mladen Gogala <gogala.mladen_at_gmail.com> wrote:

> On 5/23/22 07:43, Jonathan Lewis wrote:
>
>
> _at_Mladen Gogala <gogala.mladen_at_gmail.com>
>
> When did that change; I haven't been watching closely but the compression
> used to be done at the compute node, and HC decompression at storage cells,
> through software, except for the cases where the storage cell sent the CU
> to the compute node either to balance the CPU usage or because the extract
> from a smart scan was too large for the message buffer.
>
> Regards
> Jonathan Lewis
>
> Hi Jonathan,
>
> I think that I've read in some white paper that HCC is done on storage
> nodes, transparently to the compute nodes, as of X7. I'll look for the
> paper and let you know.
>
> Regards
>
>
> --
> Mladen Gogala
> Database Consultant
> Tel: (347) 321-1217https://dbwhisperer.wordpress.com
>
>

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