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From Jonathan Lacefield <jlacefi...@datastax.com>
Subject Re: Worse perf after Row Caching version 1.2.5:
Date Tue, 11 Feb 2014 16:42:39 GMT
Hello,

  Please paste the output of cfhistograms for these tables.  Also, what
does your environment look like, number of nodes, disk drive configs,
memory, C* version, etc.

Thanks,

Jonathan

Jonathan Lacefield
Solutions Architect, DataStax
(404) 822 3487
<http://www.linkedin.com/in/jlacefield>


<http://www.datastax.com/what-we-offer/products-services/training/virtual-training>


On Tue, Feb 11, 2014 at 10:26 AM, PARASHAR, BHASKARJYA JAY
<bp134r@att.com>wrote:

>  Hi,
>
>
>
> I have two tables and I enabled row caching for both of them using CQL.
> These two CF's are very small with one about 300 rows and other < 2000
> rows. The rows themselves are small.
>
> Cassandra heap: 8gb.
>
> a.       alter table TABLE_X with caching = 'rows_only';
>
> b.      alter table TABLE_Y with caching = 'rows_only';
>
> I also changed row_cache_size_in_mb: 1024 in the Cassandra.yaml file.
>
> After extensive testing, it seems the performance of Table_X degraded from
> 600ms to 750ms and Table_Y gained about 10 ms (from 188ms to 177 ms).
>
> More Info
>
> Table X is always queried with "Select * from Table_X";  Cfstats in
> Table_X shows Read Latency: NaN ms. I assumed that since we select all the
> rows, the entire table would be cached.
>
> Table_Y has a secondary index and is queried on that index.
>
>
>
>
>
> Would appreciate any input why the performance is worse and how to enable
> row caching for these two tables.
>
>
>
> Thanks
>
> Jay
>
>
>
>
>

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