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From Daniel Chia <danc...@coursera.org>
Subject Re: Less frequent flushing with LCS
Date Mon, 02 Mar 2015 21:13:28 GMT
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
>

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