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From aaron morton <aa...@thelastpickle.com>
Subject Re: Quorum reads and response time
Date Fri, 12 Jul 2013 08:15:23 GMT
> But when I run the same query with consistency level as Quorum, it is taking ~2.3 seconds.
 It feels as if querying of the nodes are in sequence.  
No. 

As Sankalp says look for GC issues. If none then take a look at how much data you are pulling
back, and tell us what sort of query you are using. 

Cheers

-----------------
Aaron Morton
Cassandra Consultant
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 11/07/2013, at 7:10 AM, sankalp kohli <kohlisankalp@gmail.com> wrote:

> The coordinator node has to merge the results from 2 nodes and the request is done in
parallel. I have seen lot of GC pressure with range queries because of tombstones. 
> Can you see logs to see if there is lot of GC going on. Also try to have GC log enabled.

> 
> 
> On Wed, Jul 10, 2013 at 9:57 AM, Baskar Duraikannu <baskar.duraikannu.db@gmail.com>
wrote:
> Just adding few other details to my question.
> 
> - We are using RandomPartitioner
> - 256 virtual nodes configured. 
> 
> 
> On Wed, Jul 10, 2013 at 12:54 PM, Baskar Duraikannu <baskar.duraikannu.db@gmail.com>
wrote:
> I have a 3 node cluster with RF=3.  All nodes are running. I have a table with 39 rows
and ~44,000 columns evenly spread across 39 rows. 
> 
> When I do range slice query on this table with consistency of one, it returns the data
back in about  ~600 ms.  I tried the same from all of the 3 nodes,no matter which node I ran
it from, queries were answered in 600 ms for consistency level of one.
> 
> But when I run the same query with consistency level as Quorum, it is taking ~2.3 seconds.
 It feels as if querying of the nodes are in sequence.  
> 
> Is this normal? 
> 
> --
> Regards,
> Baskar Duraikannu
> 
> 
> 


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