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From Franc Carter <franc.car...@sirca.org.au>
Subject Re: active/pending queue lengths
Date Tue, 14 Feb 2012 12:17:43 GMT
On Tue, Feb 14, 2012 at 8:01 PM, aaron morton <aaron@thelastpickle.com>wrote:

> And the output from tpstats is ?
>


I can't reproduce it at the moment ;-(

nodetool is throwing 'Failed to retrieve RMIServer stub:'  - which I'm
guessing/hoping is related to the stalled bootstrap.


>
> A
>
>   -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 14/02/2012, at 12:43 PM, Franc Carter wrote:
>
> On Tue, Feb 14, 2012 at 6:06 AM, aaron morton <aaron@thelastpickle.com>wrote:
>
>> What CL are you reading at ?
>>
>
> Quorum
>
>
>>
>> Write ops go to RF number of nodes, read ops go to RF number of nodes 10%
>> (the default probability that Read Repair will be running) of the time and
>> CL number of nodes 90% of the time. With 2 nodes and RF 2 the QUOURM is 2,
>> every request will involve all nodes.
>>
>
> Yep, the thing tat confuses is the different behaviour for reading from
> one node versus two
>
>
>>
>> As to why the pending list gets longer, do you have some more info ? What
>> process are you using to measure ? It's hard to guess why. In this setup
>> every node will have the data and should be able to do a local read and
>> then on the other node.
>>
>
> I have four pycassa clients, two making requests to one server and two
> making requests to the other (or all four making requests to the same
> server). The requested keys don't overlap and I would expect/assume the
> keys are in the keycache
>
> I am looking at the output of nodetool -h tpstats
>
> cheers
>
>
>> Cheers
>>
>>
>>   -----------------
>> Aaron Morton
>> Freelance Developer
>> @aaronmorton
>> http://www.thelastpickle.com
>>
>> On 14/02/2012, at 12:47 AM, Franc Carter wrote:
>>
>>
>> Hi,
>>
>> I've been looking at tpstats as various test queries run and I noticed
>> something I don't understand.
>>
>> I have a two node cluster with RF=2 on which I run 4 parallel queries,
>> each job goes through a list of keys doing a multiget for 2 keys at a time.
>> If two of the queries go to one node and the other two go to a different
>> node then the pending queue on the node gets much longer than if they all
>> go to the one node.
>>
>> I'm clearly missing something here as I would have expected the opposite
>>
>> cheers
>>
>> --
>> *Franc Carter* | Systems architect | Sirca Ltd
>>  <marc.zianideferranti@sirca.org.au>
>> franc.carter@sirca.org.au | www.sirca.org.au
>> Tel: +61 2 9236 9118
>>  Level 9, 80 Clarence St, Sydney NSW 2000
>> PO Box H58, Australia Square, Sydney NSW 1215
>>
>>
>>
>
>
> --
> *Franc Carter* | Systems architect | Sirca Ltd
>  <marc.zianideferranti@sirca.org.au>
> franc.carter@sirca.org.au | www.sirca.org.au
> Tel: +61 2 9236 9118
>  Level 9, 80 Clarence St, Sydney NSW 2000
> PO Box H58, Australia Square, Sydney NSW 1215
>
>
>


-- 

*Franc Carter* | Systems architect | Sirca Ltd
 <marc.zianideferranti@sirca.org.au>

franc.carter@sirca.org.au | www.sirca.org.au

Tel: +61 2 9236 9118

Level 9, 80 Clarence St, Sydney NSW 2000

PO Box H58, Australia Square, Sydney NSW 1215

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