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From Michael Kjellman <mkjell...@barracuda.com>
Subject Re: Column Slice Query performance after deletions
Date Sat, 02 Mar 2013 17:54:08 GMT
When is the last time you did a cleanup on the cf?

On Mar 2, 2013, at 9:48 AM, "VĂ­ctor Hugo Oliveira Molinar" <vhmolinar@gmail.com> wrote:

> Hello guys.
> I'm investigating the reasons of performance degradation for my case scenario which follows:
> 
> - I do have a column family which is filled of thousands of columns inside a unique row(varies
between 10k ~ 200k). And I do have also thousands of rows, not much more than 15k.
> - This rows are constantly updated. But the write-load is not that intensive. I estimate
it as 100w/sec in the column family.
> - Each column represents a message which is read and processed by another process. After
reading it, the column is marked for deletion in order to keep it out from the next query
on this row.
> 
> Ok, so, I've been figured out that after many insertions plus deletion updates, my queries(
column slice query ) are taking more time to be performed. Even if there are only few columns,
lower than 100.
> 
> So it looks like that the longer is the number of columns being deleted, the longer is
the time spent for a query.
> -> Internally at C*, does column slice query ranges among deleted columns?
> If so, how can I mitigate the impact in my queries? Or, how can I avoid those deleted
columns?

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