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From Theo Hultberg <t...@iconara.net>
Subject Re: Performance issues with CQL3 collections?
Date Wed, 26 Jun 2013 17:58:54 GMT
do I understand it correctly if I think that collection modifications are
done by reading the collection, writing a range tombstone that would cover
the collection and then re-writing the whole collection again? or is it
just the modified parts of the collection that are covered by the range
tombstones, but you still get massive amounts of them and its just their
number that is the problem.

would this explain the slowdown of writes too? I guess it would if
cassandra needed to read the collection before it wrote the new values,
otherwise I don't understand how this affects writes, but that only says
how much I know about how this works.

T#


On Wed, Jun 26, 2013 at 10:48 AM, Fabien Rousseau <fabien@yakaz.com> wrote:

> Hi,
>
> I'm pretty sure that it's related to this ticket :
> https://issues.apache.org/jira/browse/CASSANDRA-5677
>
> I'd be happy if someone tests this patch.
> It should apply easily on 1.2.5 & 1.2.6
>
> After applying the patch, by default, the current implementation is still
> used, but modify your cassandra.yaml to add the following one :
> interval_tree_provider: IntervalTreeAvlProvider
>
> (Note that implementations should be interchangeable, because they share
> the same serializers and deserializers)
>
> Also, please note that this patch has not been reviewed nor intensively
> tested... So, it may not be "production ready"
>
> Fabien
>
>
>
>
>
>
>
> 2013/6/26 Theo Hultberg <theo@iconara.net>
>
>> Hi,
>>
>> I've seen a couple of people on Stack Overflow having problems with
>> performance when they have maps that they continuously update, and in
>> hindsight I think I might have run into the same problem myself (but I
>> didn't suspect it as the reason and designed differently and by accident
>> didn't use maps anymore).
>>
>> Is there any reason that maps (or lists or sets) in particular would
>> become a performance issue when they're heavily modified? As I've
>> understood them they're not special, and shouldn't be any different
>> performance wise than overwriting regular columns. Is there something
>> different going on that I'm missing?
>>
>> Here are the Stack Overflow questions:
>>
>>
>> http://stackoverflow.com/questions/17282837/cassandra-insert-perfomance-issue-into-a-table-with-a-map-type/17290981
>>
>>
>> http://stackoverflow.com/questions/17082963/bad-performance-when-writing-log-data-to-cassandra-with-timeuuid-as-a-column-nam/17123236
>>
>> yours,
>> Theo
>>
>
>
>
> --
> Fabien Rousseau
> *
> *
>  <aurore@yakaz.com>www.yakaz.com
>

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