incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Manu Zhang <owenzhang1...@gmail.com>
Subject Re:
Date Mon, 01 Oct 2012 00:42:31 GMT
Sorry, the line "I still don't see it in jconsole" is ambiguous. I mean
that I don't find a change of rowcache size in jconsole and neither
performance gain. cfstats gives either 0 or NaN.

On Mon, Oct 1, 2012 at 8:17 AM, aaron morton <aaron@thelastpickle.com>wrote:

> I still don't see it in jconsole.
>
> It's part of the CF definition.
>
> Check the docs for CLI or CQL which ever you are using.
>
> how long would you expect to cost to read a column family of 150000 rows
> if it fits into row cache entirely? It takes me around 7s now
>
> Assuming you are talking about the client side timing for reading 150,000
> rows with several columns each this does not sound too crazy.
>
> Check the server side timing by calling nodetool cfstats before and after
> the query, the recent stats will be be since the last time cfstats was
> called.
>
> Cheers
>
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 27/09/2012, at 2:32 PM, Manu Zhang <owenzhang1990@gmail.com> wrote:
>
> I still don't see it in jconsole. BTW, how long would you expect to cost
> to read a column family of 150000 rows if it fits into row cache entirely?
> It takes me around 7s now. My experiment is done on a single node.
>
> On Thu, Sep 27, 2012 at 6:00 AM, aaron morton <aaron@thelastpickle.com>wrote:
>
>> Set the caching strategy for the CF to be ROWS_ONLY.
>>
>> Cheers
>>
>>   -----------------
>> Aaron Morton
>> Freelance Developer
>> @aaronmorton
>> http://www.thelastpickle.com
>>
>> On 26/09/2012, at 2:18 PM, Manu Zhang <owenzhang1990@gmail.com> wrote:
>>
>> The DEFAULT_CACHING_STRATEGY is Caching.KEYS_ONLY but even configuring
>> row cache size to be greater zero
>>  won't enable row cache. Why?
>>
>> On Wed, Sep 26, 2012 at 9:44 AM, Manu Zhang <owenzhang1990@gmail.com>wrote:
>>
>>> I wonder now if "get_range_slices" call will ever look for data in row
>>> cache. I don't see it in the codebase. Only the "get" call will check row
>>> cache?
>>>
>>>
>>> On Wed, Sep 26, 2012 at 12:11 AM, Charles Brophy <cbrophy@zulily.com>wrote:
>>>
>>>> There are settings in cassandra.yaml that will _gradually_ reduce the
>>>> available cache to zero if you are under constant memory pressure:
>>>>
>>>>  # Set to 1.0 to disable.  <snip>
>>>> reduce_cache_sizes_at: *
>>>> reduce_cache_capacity_to: *
>>>>
>>>> My experience is that the cache size will not return to the configured
>>>> size until a service restart if you leave this enabled.  The text of this
>>>> setting is not explicit about the long-term cache shrinkage, so it's easy
>>>> to think that it will restore the cache to its configured size after the
>>>> pressures have subsided. It won't.
>>>>
>>>> Charles
>>>>
>>>> On Tue, Sep 25, 2012 at 8:14 AM, Manu Zhang <owenzhang1990@gmail.com>wrote:
>>>>
>>>>> I've enabled row cache and set its capacity to 10MB but when I check
>>>>> its size in jconsole it's always 0. Isn't it that a row will be written
to
>>>>> row cache if it isn't there when I read the row? I've bulk loaded the
data
>>>>> into disk so row cache is crucial to the performance.
>>>>
>>>>
>>>>
>>>
>>
>>
>
>

Mime
View raw message