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From Ken Hancock <ken.hanc...@schange.com>
Subject Re: Memtable flush blocking writes
Date Tue, 24 Sep 2013 15:55:54 GMT
This is on Cassandra 1.2.9 though packaged into DSE which I suspect may
come into play here.  I didn't really get to the bottom of it other than to
up the queue to 32 which is about the number of CFs I have.  After that,
mutation drops disappeared and the FlushWriter blocks went away.


On Mon, Sep 23, 2013 at 6:03 PM, Robert Coli <rcoli@eventbrite.com> wrote:

> On Fri, Aug 23, 2013 at 10:35 AM, Ken Hancock <ken.hancock@schange.com>wrote:
>
>> I appear to have a problem illustrated by
>> https://issues.apache.org/jira/browse/CASSANDRA-1955. At low data
>> rates, I'm seeing mutation messages dropped because writers are
>> blocked as I get a storm of memtables being flushed. OpsCenter
>> memtables seem to also contribute to this:
>>
> ...
>
>> Now I can increase memtable_flush_queue_size, but it seems based on
>> the above that in order to solve the problem, I need to set this to
>> count(CF). What's the downside of this approach? It seems a backwards
>> solution to the real problem...
>>
>
> What version of Cassandra? Did you ever get to the bottom of this?
>
> =Rob
>
>


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