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From aaron morton <aa...@thelastpickle.com>
Subject Re: secondary index performance
Date Tue, 05 Jul 2011 00:27:30 GMT
> Is the assumption that rows/keys cached is inherited correct?  Is there any way to see
cfstats on secondary index sub-column families?

They are inherited, but AFAIK only at the time the secondary index is created. You would need
to drop and re-create the secondary index to see it change. 

cfstats for secondary index CF's are available via JMX / JConsole. 

Cheers	
-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com

On 4 Jul 2011, at 10:12, Jeremy Hanna wrote:

> 
> On Jul 3, 2011, at 4:29 PM, Jeremy Hanna wrote:
> 
>> Anyone know if secondary index performance should be in the 100-500 ms range.  That's
what we're seeing right now when doing lookups on a single value.  We've increased keys_cached
and rows_cached to 100% for that column family and assume that the secondary index gets the
same attributes.  I've also reduced read_repair_chance to 0.2 because it doesn't get overwritten
very frequently.
>> 
>> Is the assumption that rows/keys cached is inherited correct?  Is there any way to
see cfstats on secondary index sub-column families?
> 
> the answer appears to be no and no.
> 
> Trying some other stuff with tools mentioned here: http://spyced.blogspot.com/2010/01/linux-performance-basics.html
but not seeing anything particularly disk bound, though await (from iostat -x) seems high
on one of the devices.
> 
> One of our guys said he pointed at our realtime nodes (instead of analytic nodes) but
said the performance was worse.  Granted our analytic nodes are m4.xl and our realtime nodes
are currently large, but still with no load on them, it should be quite fast I would think.
> 
>> 
>> Thanks,
>> 
>> Jeremy
> 


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