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From Apoorva Gaurav <apoorva.gau...@myntra.com>
Subject Re: Read performance in map data type
Date Fri, 04 Apr 2014 05:41:34 GMT
On Fri, Apr 4, 2014 at 3:32 AM, Robert Coli <rcoli@eventbrite.com> wrote:

> On Thu, Apr 3, 2014 at 12:20 AM, Apoorva Gaurav <apoorva.gaurav@myntra.com
> > wrote:
>
>> At the client side we are getting a latency of ~350ms, we are using
>> datastax driver 2.0.0 and have kept the fetch size as 500. And these are
>> coming while reading rows having ~200 columns.
>>
>
> And you're sure that the 300ms between what cassandra reports and what
> your app reports are not just network/serialization time?
>
We are using the datastax 2.0.0 driver. This latency is for the execute
command. We already have the prepared statement cached in app layer before
calling execute.

>
> What do you believe the latency "should" be?
>
If we store the same data as a json using text data type i.e (studentID
int, subjectMarksJson text) we are getting a latency of ~10ms from the same
client for even bigger. I understand that json is not the preferred storage
for cassandra and will loose various flexibility which a proper tabular
approach provides. But such a huge jump in read latency is killer. I'm
pastebin-ing the histogram for json storage as well
http://pastebin.com/RiW6hMb2.

>
> =Rob
>
>



-- 
Thanks & Regards,
Apoorva

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