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From Sandeep Tata <sandeep.t...@gmail.com>
Subject Re: cassandra's performance?
Date Thu, 04 Jun 2009 01:11:22 GMT
Apart from logging, given enough memory, you could get Cassandra to
behave almost like an in-memory system.

Turning off logging is relatively straightforward.
If you turn off periodic flushing of memtables and have the thresholds
high enough (a little more tricky), you're done -- chances are the
read path and the write path will never hit disk.


On Wed, Jun 3, 2009 at 5:48 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
> Cassandra is not designed to work memory-only.  It's designed designed
> to use disk for durability and to accommodate using large sets of
> data, letting the OS use memory as a huge cache for that.  For typical
> data use patterns (where a relatively small amount is "hot") this will
> be a much better use of hardware than memory-only.
>
> On Wed, Jun 3, 2009 at 7:44 PM, lichun li <lilichun@gmail.com> wrote:
>> Thank you!
>> The "how fast is it" section says:"In a nutshell, Cassandra is much
>> faster than relational databases, and much slower than memory-only
>> systems or systems that don't sync each update to disk."
>> Can Cassandra work in a memory-only mode? Can it be done by just
>> changing configuration?
>>
>> On Wed, Jun 3, 2009 at 10:38 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
>>> We're basically in a roll-your-own benchmark state.  Johan can
>>> probably give some pointers:
>>> http://blog.oskarsson.nu/2009/05/vpork.html.  Also see the "how fast
>>> is it" section here:
>>> http://spyced.blogspot.com/2009/05/cassandra-03-release-candidate-and.html
>>>
>>> -Jonathan
>>>
>>> On Wed, Jun 3, 2009 at 3:06 AM, lichun li <lilichun@gmail.com> wrote:
>>>> I can't find cassandra's performance data, such as throughput. Does
>>>> anyone know where to find these data?
>>>>
>>>> --
>>>> Sincerely yours,
>>>>
>>>> Lichun Li
>>>> Mobile Life New Media Lab, BUPT
>>>>
>>>
>>
>>
>>
>> --
>> Sincerely yours,
>>
>> Lichun Li
>> Mobile Life New Media Lab, BUPT
>>
>

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