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From Mohit Anchlia <mohitanch...@gmail.com>
Subject Re: WARN [Memtable] live ratio
Date Fri, 03 Feb 2012 16:31:14 GMT
On Fri, Feb 3, 2012 at 7:32 AM, Jonathan Ellis <jbellis@gmail.com> wrote:
> It's a warn because it's nonsense for the JVM to report that an column
> + overhead, takes less space than just the column data itself.
>

But is there any action we need to take, or worry about? We trigger
alerts based on WARN and ERROR. But if there is nothing to do then it
probably is just an INFO.
> On Tue, Jan 31, 2012 at 9:41 PM, Mohit Anchlia <mohitanchlia@gmail.com> wrote:
>> I guess this is not really a WARN in that case.
>>
>> On Tue, Jan 31, 2012 at 4:29 PM, aaron morton <aaron@thelastpickle.com> wrote:
>>> The ratio is the ratio of serialised bytes for a memtable to actual JVM
>>> allocated memory. Using a ratio below 1 would imply the JVM is using less
>>> bytes to store the memtable in memory than it takes to store it on disk
>>> (without compression).
>>>
>>> The ceiling for the ratio is 64.
>>>
>>> The ratio is calculated periodically so if the workload changes, such as
>>> system start up, the number will lag behind. I would guess numbers less than
>>> 1 mean the memtable does not have any data.
>>>
>>> Cheers
>>>
>>> -----------------
>>> Aaron Morton
>>> Freelance Developer
>>> @aaronmorton
>>> http://www.thelastpickle.com
>>>
>>> On 1/02/2012, at 8:27 AM, Radim Kolar wrote:
>>>
>>>
>>>  but a ration of<  1 may occur
>>>
>>> for column families with  a very high update to insert ratio.
>>>
>>> better to ask why minimum ratio is 1.0. What harm can be done with using <
>>> 1.0 ratio?
>>>
>>>
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com

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