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From Jimmy Lin <>
Subject Re: row caching for frequently updated column
Date Wed, 30 Apr 2014 04:41:02 GMT
thanks all for the pointers.

let' me see if I can put the sequences of event together ....

people mis-understand/mis-use row cache, that cassandra cached the entire
row of data even if you are only looking for small subset of the row data.
select single_column from a_wide_row_table
will result in entire row cached even if you are only interested in one
single column of a row.

and because of potential misuse of heap memory, Cassandra 2.0 remove heap
cache, and only support off-heap cache, which has a side effect that write
will invalidate the row cache(my original question)

the coming 2.1 Cassandra will offer true cache by query, so the cached data
will be much more efficient even for wide rows(it cached what it needs).

do I get it right?
for the new 2.1 row caching, is it still true that a write or update to the
row will still invalidate the cached row ?

On Tue, Apr 29, 2014 at 3:00 PM, Robert Coli <> wrote:

> On Tue, Apr 29, 2014 at 1:53 PM, Brian Lam <> wrote:
>> Are these issues 'resolved' only in 2.0 or later release?
>> What about 1.2 version?
> As I understand it :
> 1.2 version has the on-heap row cache and off-heap row cache. It does not
> have the new "partition" cache.
> 2.0 version has only the off-heap row cache. It does not have the on-heap
> row cache or the new "partition" cache.
> 2.1 version has the new "partition" cache.
> In summary, you probably don't want to use any of these half-baked,
> immature internal row/etc. "caches" unless you are very, very certain that
> you have an ideal case for them.
> =Rob

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