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From Stu Hood <stuh...@gmail.com>
Subject Re: Columns values(integer) need frequent updates/ increments
Date Sun, 10 Apr 2011 02:33:51 GMT
Also, if you are concerned that your updates are being scattered through
multiple files, there is a metric exposed via JMX that can tell you how many
SSTables your reads need to hit: see the (Recent)SSTablePerRead histogram on
each column family.

Many write patterns won't be affected by the existing implementation, but
constant updates to rows will lower your performance until a solution to
#1608 is available.


On Sat, Apr 9, 2011 at 7:22 PM, Stu Hood <stuhood@gmail.com> wrote:

> Sorry, I meant to say #2319:
> https://issues.apache.org/jira/browse/CASSANDRA-2319
>
>
> On Sat, Apr 9, 2011 at 6:04 PM, Stu Hood <stuhood@gmail.com> wrote:
>
>> If an SSTable contains an update for a row (row, not just column), we need
>> to read from it. See #1608 for some of the ideas that have been floated on
>> how to improve this situation: the core ones are 1. partitioning local data
>> so that the the number of files involved in a read is smaller, 2. adding
>> support for "superceding" data in older files so that they can be skipped.
>> #2316 will provide the beginning of a solution to this problem for wide
>> rows.
>>
>>
>> On Sat, Apr 9, 2011 at 5:52 PM, mcasandra <mohitanchlia@gmail.com> wrote:
>>
>>> That I understand but my basic quesiton was how does it know that there
>>> are
>>> multiple updates that have occurred on the same column? and how does it
>>> efficiently knows which sstable have these updates?
>>>
>>> --
>>> View this message in context:
>>> http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Columns-values-integer-need-frequent-updates-increments-tp6251464p6258033.html
>>> Sent from the cassandra-user@incubator.apache.org mailing list archive
>>> at Nabble.com.
>>>
>>
>>
>

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