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From Kevin Burton <bur...@spinn3r.com>
Subject Re: Tune cache MB settings per table.
Date Mon, 02 Jun 2014 00:01:01 GMT
Good question. still migrating.. but we don't want to paint ourselves into
a corner.

There's an interesting line between premature optimization and painting
yourself into a corner ;)

Best to get it right in between both extremes.


On Sun, Jun 1, 2014 at 4:30 PM, Colin <colpclark@gmail.com> wrote:

> Have you been unable to achieve your SLA's using Cassandra out of the box
> so far?
>
> Based upon my experience, trying to tune Cassandra before the app is done
> and without simulating real world load patterns, you might actually be
> doing yourself a disservice.
>
> --
> Colin
> 320-221-9531
>
>
> On Jun 1, 2014, at 6:08 PM, Kevin Burton <burton@spinn3r.com> wrote:
>
> Not in our experience… We've been using fadvise don't need to purge pages
> that aren't necessary any longer.
>
> Of course YMMV based on your usage.  I tend to like to control everything
> explicitly instead of having magic.
>
> That's worked out very well for us in the past so it would be nice to
> still have this on cassandra.
>
>
> On Sun, Jun 1, 2014 at 12:53 PM, Colin <colin@clark.ws> wrote:
>
>> The OS should handle this really well as long as your on v3 linux
>> kernel....
>>
>> --
>> *Colin Clark*
>> +1-320-221-9531
>>
>>
>> On Jun 1, 2014, at 2:49 PM, Kevin Burton <burton@spinn3r.com> wrote:
>>
>> It's possible to set caching to:
>>
>> all, keys_only, rows_only, or none
>>
>> .. for a given table.
>>
>> But we have one table which is MASSIVE and we only need the most recent
>> 4-8 hours in memory.
>>
>> Anything older than that can go to disk as the queries there are very
>> rare.
>>
>> … but I don't think cassandra can do this (which is a shame).
>>
>> Another option is to partition our tables per hour… then tell the older
>> tables to cache 'none'…
>>
>> I hate this option though.  A smarter mechanism would be to have a
>> compaction strategy that created an SSTable for every hour and then had
>> custom caching settings for that table.
>>
>> The additional upside for this is that TTLs would just drop the older
>> data in the compactor..
>>
>> --
>>
>> Founder/CEO Spinn3r.com
>> Location: *San Francisco, CA*
>> Skype: *burtonator*
>> blog: http://burtonator.wordpress.com
>> … or check out my Google+ profile
>> <https://plus.google.com/102718274791889610666/posts>
>> <http://spinn3r.com>
>> War is peace. Freedom is slavery. Ignorance is strength. Corporations are
>> people.
>>
>>
>
>
> --
>
> Founder/CEO Spinn3r.com
> Location: *San Francisco, CA*
> Skype: *burtonator*
> blog: http://burtonator.wordpress.com
> … or check out my Google+ profile
> <https://plus.google.com/102718274791889610666/posts>
> <http://spinn3r.com>
> War is peace. Freedom is slavery. Ignorance is strength. Corporations are
> people.
>
>


-- 

Founder/CEO Spinn3r.com
Location: *San Francisco, CA*
Skype: *burtonator*
blog: http://burtonator.wordpress.com
… or check out my Google+ profile
<https://plus.google.com/102718274791889610666/posts>
<http://spinn3r.com>
War is peace. Freedom is slavery. Ignorance is strength. Corporations are
people.

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