ailto:sylv...@datastax.com]
> Sent: Tuesday, July 19, 2011 11:40 AM
> To: user@cassandra.apache.org
> Subject: Re: How to keep only exactly column of key
>
> On Tue, Jul 19, 2011 at 10:15 AM, Lior Golan wrote:
>> Can't this capping be done (approximately) during compaction.
&g
@cassandra.apache.org
Subject: Re: How to keep only exactly column of key
On Tue, Jul 19, 2011 at 10:15 AM, Lior Golan wrote:
> Can't this capping be done (approximately) during compaction.
> Something
> like:
>
> 1. Ability to define for a column family that it's a &q
compaction
that just drop columns after the N first. It would then be on the client side
to deal with the possibility to get more that the first N ones, but as you said,
if it is for automated cleanup, that will be enough.
--
Sylvain
> From: Tupshin Harper [mailto:tups...@tupshin.com]
&g
cleanup, and not for
enforcing exactly N columns, I think this would be sufficient
From: Tupshin Harper [mailto:tups...@tupshin.com]
Sent: Tuesday, July 19, 2011 10:04 AM
To: user@cassandra.apache.org
Subject: Re: How to keep only exactly column of key
Speaking from practical experience, it is
Speaking from practical experience, it is possible to simulate this feature
by retrieving a slice of your row that only contains the most recent 100
items. You can then prevent the rows from growing out of control by checking
the size of the row and pruning it back to 100 every N writes, where N is
You can use expiring columns to say "only the last N seconds' of
data." But not counts per se for the reasons Aaron gave.
On Mon, Jul 18, 2011 at 10:22 AM, JKnight JKnight wrote:
> Dear all,
> I want to keep only 100 column of a key: when I add a column for a key, if
> the number column of key i
The Datastax post on counters says:
"Prior to 0.8, Cassandra had no simple and efficient way to count. By
“counting,” we mean here to provide an atomic increment operation in a
single column value, as opposed to counting the number of columns in a row,
or rows in a column family, both of which were
There is no support for a feature like that, and i doubt it would ever be
supported. For one there there are no locks during a write, so it's not
possible to definitively say there are 100 columns at a particular instance of
time.
You would need to read all columns and delete the ones you no l
