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From Jonathan Lacefield <jlacefi...@datastax.com>
Subject Re: row caching for frequently updated column
Date Tue, 29 Apr 2014 11:43:50 GMT
Hello,


  Iirc writing a new value to a row will invalidate the row cache for that
value.  Row cache is only populated after a read operation.
http://www.datastax.com/documentation/cassandra/2.0/cassandra/operations/ops_configuring_caches_c.html?scroll=concept_ds_n35_nnr_ck

  Cassandra provides the ability to "preheat" key and page cache, but I
don't believe this is possible for row cache.

  Hope that helps.

Jonathan


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

<http://www.datastax.com/cassandrasummit14>



On Mon, Apr 28, 2014 at 10:27 PM, Jimmy Lin <y2klyf+work@gmail.com> wrote:

> I am wondering if there is any negative impact on Cassandra write
> operation, if I turn on row caching for a table that has mostly 'static
> columns' but few frequently write columns (like timestamp).
>
> The application will frequently write to a few columns, and the
> application will also frequently query entire row.
>
> How Cassandra handle update column to a cached row?
> does it update both memtables value and also the row cached row's
> column(which dealing with memory update so it is very fast) ?
> or in order to update the cached row, entire row need to read back from
> sstable?
>
>
> thanks
>
>

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