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From Edward Capriolo <edlinuxg...@gmail.com>
Subject Re: Help on MMap of SSTables
Date Thu, 13 Dec 2012 15:36:32 GMT
This issue has to be looked from a micro and macro level. On the microlevel
the "best" way is workload specific. On the macro level this mostly boils
down to data and memory size.

Companions are going to churn cache, this is unavoidable. Imho solid state
makes the micro optimization meanless in the big picture. Not that we
should not consider tweaking flags but just saying it is hard to believe
anything like that is a game change.

On Monday, December 10, 2012, Rob Coli <rcoli@palominodb.com> wrote:
> On Thu, Dec 6, 2012 at 7:36 PM, aaron morton <aaron@thelastpickle.com>
wrote:
>> So for memory mapped files, compaction can do a madvise SEQUENTIAL
instead
>> of current DONTNEED flag after detecting appropriate OS versions. Will
this
>> help?
>>
>>
>> AFAIK Compaction does use memory mapped file access.
>
> The history :
>
> https://issues.apache.org/jira/browse/CASSANDRA-1470
>
> =Rob
>
> --
> =Robert Coli
> AIM&GTALK - rcoli@palominodb.com
> YAHOO - rcoli.palominob
> SKYPE - rcoli_palominodb
>

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