cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Dan Kinder <dkin...@turnitin.com>
Subject Re: Less frequent flushing with LCS
Date Mon, 02 Mar 2015 21:26:37 GMT
Nope, they flush every 5 to 10 minutes.

On Mon, Mar 2, 2015 at 1:13 PM, Daniel Chia <danchia@coursera.org> wrote:

> Do the tables look like they're being flushed every hour? It seems like
> the setting memtable_flush_after_mins which I believe defaults to 60
> could also affect how often your tables are flushed.
>
> Thanks,
> Daniel
>
> On Mon, Mar 2, 2015 at 11:49 AM, Dan Kinder <dkinder@turnitin.com> wrote:
>
>> I see, thanks for the input. Compression is not enabled at the moment,
>> but I may try increasing that number regardless.
>>
>> Also I don't think in-memory tables would work since the dataset is
>> actually quite large. The pattern is more like a given set of rows will
>> receive many overwriting updates and then not be touched for a while.
>>
>> On Fri, Feb 27, 2015 at 2:27 PM, Robert Coli <rcoli@eventbrite.com>
>> wrote:
>>
>>> On Fri, Feb 27, 2015 at 2:01 PM, Dan Kinder <dkinder@turnitin.com>
>>> wrote:
>>>
>>>> Theoretically sstable_size_in_mb could be causing it to flush (it's at
>>>> the default 160MB)... though we are flushing well before we hit 160MB. I
>>>> have not tried changing this but we don't necessarily want all the sstables
>>>> to be large anyway,
>>>>
>>>
>>> I've always wished that the log message told you *why* the SSTable was
>>> being flushed, which of the various bounds prompted the flush.
>>>
>>> In your case, the size on disk may be under 160MB because compression is
>>> enabled. I would start by increasing that size.
>>>
>>> Datastax DSE has in-memory tables for this use case.
>>>
>>> =Rob
>>>
>>>
>>
>>
>> --
>> Dan Kinder
>> Senior Software Engineer
>> Turnitin – www.turnitin.com
>> dkinder@turnitin.com
>>
>
>


-- 
Dan Kinder
Senior Software Engineer
Turnitin – www.turnitin.com
dkinder@turnitin.com

Mime
View raw message